# Annual Report on Form 10-K

# Great Northern Iron Ore Properties

# December 31, 2005

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# SECURITIES AND EXCHANGE COMMISSION
Washington, D.C. 20549

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# FORM 10-K

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# ANNUAL REPORT PURSUANT TO SECTION 13 OR 15(d) OF
THE SECURITIES EXCHANGE ACT OF 1934

# For the fiscal year ended December 31, 2005

# Commission File Number 1-701

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GREAT NORTHERN IRON ORE PROPERTIES
(Exact name of registrant as specified in its charter)

|Minnesota                                |  | 41-0788355          | 
|---------------------------------------- |  | ------------------- | 
|(State or Other Jurisdiction of          |  | (I.R.S. Employer    | 
|Incorporation or Organization)           |  | Identification No.) | 
|                                        
|W-1290 First National Bank Building      | 
|332 Minnesota Street                     | 
|Saint Paul, Minnesota                    |  | 55101-1361          | 
|(Address of Principal Executive Offices) |  | (Zip Code)          | 

Registrants Telephone Number, Including Area Code   651 / 224-2385

Securities registered pursuant to Section 12(b) of the Exchange Act:

|Title of Each Class                           |  | Name of Each Exchange onWhich Registered
|--------------------------------------------- |  | ----------------------------------------
|Trustees Certificates of Beneficial Interest |  | New York Stock Exchange                 

Securities registered pursuant to Section 12(g) of the Exchange ActNone

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Indicate by check mark if the registrant is a well-known seasoned issuer (as
defined in Rule 405 of the Securities Act).   Yes
  o   
No
  x

Indicate by check mark if the registrant is not required to file reports
pursuant to Section 13 or 15(d) of the Exchange Act.   Yes
  o   
No
  x

Indicate by check mark whether the registrant (1) has filed all reports
required to be filed by Section 13 or 15(d) of the Securities Exchange Act of 1934 during the preceding twelve months and (2) has
been subject to such filing requirements for the past 90 days.   Yes
  x   
No
  o

Indicate by check mark if disclosure of delinquent filers pursuant to Item
405 of Regulation S-K is not contained herein, and will not be contained, to the best of registrants knowledge, in
definitive proxy or information statements incorporated by reference in Part III of this Form 10-K or any amendment to this
Form 10-K.  x

Indicate by check mark whether the registrant is a large accelerated filer,
an accelerated filer or a non-accelerated filer (as defined in Rule 12b-2 of the Act).

Large accelerated filer
o                
Accelerated filer
x                
Non-accelerated filer    
o

Indicate by check mark whether the registrant is a shell company (as defined
in Rule 12b-2 of the Exchange Act).
  o   
No
  x

As of the last business day of the registrants most recently completed
second fiscal quarter, that being June 30, 2005, the aggregate market value of the registrants certificates (shares) of
beneficial interest held by non-affiliates of the registrant was $158,250,000 based on the closing sale price as reported on the
New York Stock Exchange  Composite Inter-Market Trading System.

The number of certificates (shares) of beneficial interest outstanding as of
the close of the period covered by this report:

Trustees Certificates of Beneficial Interest  1,500,000

DOCUMENTS INCORPORATED BY REFERENCE

Portions of the Annual Report to Certificate Holders for the year ended
December 31, 2005, attached hereto as Exhibit 13, are incorporated by reference into Part II.





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PART I

|Item 1. |  | BUSINESS
|------- |  | --------

| | The Registrant (Trust or we or
our or GNIOP) owns interests in fee, both mineral and nonmineral lands, on the Mesabi Iron Range of
Minnesota. The Registrant is a conventional trust organized under the laws of the State of Michigan pursuant to a Trust Agreement
dated December 7, 1906. Because the Trust properties and offices are all located in Minnesota, the Trust is under the jurisdiction
of the Ramsey County District Court in Saint Paul, Minnesota. Income is derived through royalties on iron ore minerals
(principally taconite) taken from these properties by lessees. The Registrant is presently involved solely with the leasing and
care of these properties. There have been no significant changes in these functions since the beginning of the fiscal year.
| | --------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------

| | The terms of the Great Northern Iron Ore Properties Trust
Agreement, created December 7, 1906, state that the Trust shall continue for twenty years after the death of the last surviving of
eighteen persons named in the Trust Agreement. The last survivor of these eighteen named in the Trust Agreement died April 6,
1995. Accordingly, the Trust terminates twenty years from April 6, 1995.
| | ---------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------

| | At the end of the Trust, that being April 6, 2015, the
certificates of beneficial interest (shares) in the Trust will cease to trade on the New York Stock Exchange and thereafter will
represent only the right to receive certain distributions payable to the certificate holders of record at the time of the
termination of the Trust. Upon termination, the Trust is obligated to distribute ratably to these certificate holders the net
monies remaining in the hands of the Trustees (after paying and providing for all expenses and obligations of the Trust), plus the
balance in the Principal Charges account (this account is explained in the Trusts Annual Report sent to all certificate
holders every year). All other Trust property (most notably the Trusts mineral properties) must be conveyed and transferred
to the reversioner (currently Glacier Park Company, a wholly owned subsidiary of Burlington Resources, Inc.) under the terms of
the Trust Agreement.
| | ---------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------

1

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|Item 1. |  | BUSINESS  Continued
|------- |  | --------------------

| | We have previously provided information in our various Securities
and Exchange Commission (SEC) filings, including our Annual Report, about the final distribution payable to the certificate
holders upon the Trusts termination. The exact final distribution, though not determinable at this time, will generally
consist of the sum of the Trusts net monies (essentially, total assets less liabilities and properties) and the balance in
the Principal Charges account, less any and all expenses and obligations of the Trust upon termination. To offer a hypothetical
example, without factoring in any expenses and obligations of the Trust upon its termination, and using the financial statement
values as of December 31, 2005, the net monies were approximately $10.5 million and the Principal Charges account balance was
approximately $5.3 million, resulting in a final distribution payable of approximately $15.8 million, or about $10.53 per share.
After payment of this final distribution, the certificates of beneficial interest (shares) would be cancelled and will have no
further value. It is important to note, however, that the actual net monies on hand and the Principal Charges account balance will
most likely fluctuate during the ensuing years and will not be final until after the termination and wind-down of the
Trust. We offer this example to further inform investors about the conceptual nature of the final distribution and do not imply or
guarantee a specific known final distribution amount.
| | --------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------

| | The
raw materials essential to the business of the Registrant are the minerals contained in
properties owned and leased by the Registrant. Because we lease our properties to mining
interests that control the amount of ore production, we do not have direct control over
the tonnage mined from our properties; we are solely involved with administering the
leases on the properties. Since operating companies insist on freedom to move from
property to property as mining requirements dictate, such changes in production cannot be
precisely reduced to financial forecasts.
| | ----------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------

| | The
Registrant owns mineral interests in 12,033 acres on the Mesabi Iron Formation, including
approximately 7,443 acres which are wholly owned, 1,080 acres in which the
Registrant is a tenant in common with a 91% interest, 3,350 acres in tenancy in common
with a 50% interest and 160 acres in tenancy in common with other fractional interests.
Of said total, 7,152 acres are under lease, and 4,881 acres are unleased.
| | ---------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------

| | The
Registrant cannot estimate at this time any tonnage for nonmagnetic taconite because of
lack of drilling, testing and any established large-scale commercial treatment method for
Mesabi Iron Range nonmagnetic taconite. To give a better perspective on magnetic
taconite, our engineers estimate that the magnetic taconite under lease as of December
31, 2005, was equivalent to approximately 329,708,000 tons of pellets.
| | ------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------

2

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|Item 1. |  | BUSINESS  Continued
|------- |  | --------------------

| | Present leases provide for minimum royalties aggregating
approximately $3,670,000 for the year 2006 even if no taconite is mined. This entire amount is attributable to long-term taconite
leases.
| | --------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------

| | None of the Registrants leases provide for any right of
renewal by the lessees upon expiration, even though unmined minerals might remain. Any extension of any such terminating lease
would have to be negotiated in the same manner as unleased properties.
| | --------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------

| | All leases granted by the Registrant, except some covering
remnants of natural ore, have provisions for escalation of royalty rates. Most of the taconite royalty rates are escalated on the
basis of the price of pellets, the iron content, the Producers Price Index (PPI) (All Commodities), the PPI (Iron and Steel
subgroup) or certain combinations of the above.
| | ------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------

| | There are other landowners on the Mesabi Iron Range, including
mining companies and numerous other private fee owners. Accordingly, firm data on competitive conditions in the iron ore industry
is not available. Iron ore is also available from a number of other sources. However, the generally close proximity of our lands
to the mining facilities tends to provide a competitive advantage to the Trust. In addition, other typical competitive factors
include royalty rates, quality and geological characteristics of the ore bodies available, production guarantees granted to the
fee owners, minimum royalty provisions and other matters. The Registrants non-taconite shipments have ceased as a source of
income because the ore deposits have, for practical purposes, been exhausted. The mining of taconite by lessees is the most
important part of our business. Future development depends, to a large part, on the demand for taconite from our properties by
mining companies.
| | ----------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------

| | The Registrants royalty income is dependent on the number of
tons of taconite shipped from its properties by the lessees, royalty rates, minimum royalties collected and liquidation of minimum
royalties collected. Following is a summary of shipments by lessee (operating facility) during 2005, 2004 and 2003:
| | --------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------

|                                 | Tons Shipped
|-------------------------------- | ------------
|
|U.S. Steel Corporation  Minntac |             
|Hibbing Taconite Company         |             
|U.S. Steel Corporation  Keetac  |             
|                                 |             
|                                 |             
|                                 |             

3

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|Item 1. |  | BUSINESS  Continued
|------- |  | --------------------

| | At December 31, 2005, the Registrant employed ten persons. We have
been engaged in only one line of business, namely the leasing and maintenance of our mineral properties. Our business is not
seasonal, but income depends upon production by mining companies which lease our properties. We have no operations in foreign
countries and have no customers or lessees in foreign countries.
| | ----------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------

| | As previously reported, Section 646 of the Tax Reform Act of 1986,
as amended, provided a special elective provision under which the Trust was allowed to convert from taxation as a corporation to
that of a grantor trust. Pursuant to an Order of the Ramsey County District Court, the Trustees filed the Section 646 election
with the Internal Revenue Service on December 30, 1988. On January 1, 1989, the Trust became exempt from federal and Minnesota
corporate income taxes. For years 1989 and thereafter, certificate holders are taxed on their allocable share of the Trusts
income whether or not the income is distributed. For certificate holder tax purposes, the Trusts income is determined on an
annual basis, one-fourth then being allocated to each quarterly record date.
| | --------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------

| | The Trustees provided annual income tax information in January
2006 to certificate holders of record with holdings on any of the four quarterly record dates during 2005. This information
included a:
| | ------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------

| | Substitute Form 1099-MISC  This form reported ones
2005 allocable share of income from the Trust, distributions declared and any taxes withheld. (Foreign certificate holders
received a Form 1042S.)
| | -------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------

| | Trust Supplemental Statement  This statement reported the
number of units (shares) held on any of the four quarterly record dates in 2005.
| | -------------------------------------------------------------------------------------------------------------------------------------------

| | Tax Return Guide  This guide instructed the certificate
holders as to the preparation of their income tax returns with respect to income allocated from the Trust and various deductions
allowable.
| | ----------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------

| | The Registrant does not maintain a website and therefore we do not
make available through a website the annual, quarterly and other reports that we file with the SEC. We will furnish to investors
free of charge, upon request, a paper copy of the reports that we file with the SEC. We will also furnish to investors free of
charge, upon request, a paper copy of the Trusts Code of Ethics, which has been signed and affirmed by all employees,
Trustees and officers of the Trust. To request any of these documents, please contact the Trust office.
| | -----------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------

4

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|Item 1. |  | BUSINESS  Continued
|------- |  | --------------------

| | The following is a listing of the Registrants current
leases:
| | --------------------------------------------------------------

|Lease                                                      |  | Number ofLeased Acres |  | GNIOPInterest |   | County Location      |  | Term                   |  | LesseeTerminationProvision
|---------------------------------------------------------- |  | --------------------- |  | ------------- | - | -------------------- |  | ---------------------- |  | --------------------------
|Bennett Annex                                              |  | 237                   |  | 100           | % | St. Louis            |  | 1/1/1965 to 12/31/2039 |  | 1 year                    
|Carmi-Campbell                                             |  | 1,597                 |  | 100           |   | St. Louis            |  | 7/1/1959 to 12/31/2010 |  | 1 year                    
|Enterprise-Mississippi   (incl. Miss. #3 & Sect. 18 mines) |  | 776                   |  | 100           |   | St. Louis and Itasca |  | 1/1/1961 to 12/31/2010 |  | 6 months                  
|Hanna Taconite #1                                          |  | 40                    |  | 100           |   | Itasca               |  | 4/1/1962 to 12/31/2010 |  | 6 months                  
|Gray Annex                                                 |  | 40                    |  | 50            |   | St. Louis            |  | 1/1/1974 to 1/1/2049   |  | 1 year                    
|                                                          
|Ontario 50%                                                |  | 1,397                 |  | 50            |   | St. Louis and Itasca |  | 7/1/1978 to 12/31/2016 |  | 1 year                    
|Ontario 100%                                               |  | 400                   |  | 100           |   | St. Louis and Itasca |  | 7/1/1978 to 12/31/2016 |  | 1 year                    
|Ontario #3                                                 |  | 80                    |  | 25            |   | St. Louis            |  | 1/2/1993 to 12/31/2016 |  | 1 year                    
|Mahoning                                                   |  | 980                   |  | 100           |   | St. Louis and Itasca |  | 1/1/1979 to 12/31/2026 |  | 1 year                    
|Russell Annex/Theodore                                     |  | 200                   |  | 50            |   | Itasca               |  | 1/1/1966 to 12/31/2040 |  | 1 year                    
|                                                          
|L & W/Leetonia                                             |  | 80                    |  | 50            |   | St. Louis            |  | 1/1/2005 to 12/31/2014 |  | 1 year                    
|South Stevenson                                            |  | 180                   |  | 100           |   | St. Louis            |  | 4/1/1966 to 4/1/2041   |  | 1 year                    
|Minntac                                                    |  | 1,725                 |  | 100           |   | St. Louis            |  | 1/1/1959 to 12/31/2057 |  | 6 months                  
|Atkins                                                     |  | 160                   |  | 91            |   | St. Louis            |  | 8/1/1984 to 7/31/2009  |  | 6 months                  

5

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|Item 1A. |  | RISK FACTORS
|-------- |  | ------------

| | Certain expectations and projections regarding future performance
of the Registrant referenced in this report are forward-looking statements. These expectations and projections are based on
currently available industry and financial data and may be subject to certain events and uncertainties beyond our control. We
caution readers that in addition to factors described elsewhere in this report, the following factors and comments, among others,
could cause our operations and financial results to differ materially from the expectations and projections contained in the
forward-looking statements.
| | ----------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------

| | The Registrant is dependent on a limited number of customers.
Our lessees (customers) primarily include Minntac and Keewatin Taconite Company (Keetac), owned and operated by
United States Steel Corporation, and Hibbing Taconite Company (Hibtac), owned by Mittal Steel USA, Cleveland Cliffs
Inc. and Stelco, and operated by Cleveland Cliffs Inc. Because our revenues are primarily dependent upon a limited number of
customers, there are associated inherent risks resulting therefrom. While the steel and taconite industries are generally having
good years, any significant adverse event at any of our primary lessees, or the loss of any of our primary lessees, could
materially adversely affect our future financial results.
| | -------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------

| | The Registrant is subject to market forces beyond its control.
A decline in market demand for steel, and correspondingly taconite, could adversely affect our financial results. However,
other related and sometimes compensating factors include our lessees operating levels, ore body quality, metallurgical and
geological characteristics, proximity of our lands, extreme weather conditions and labor contracts at the mines. Though we are not
a party to these labor contracts, all pertinent labor contracts affecting production from our lands have been ratified by the
steelworkers and extend until mid-2008.
| | ------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------

| | The Registrants royalty rates are typically tied to producer
price indices. Royalty rates can fluctuate due to the escalation and de-escalation of producer price indices as a result
of provisions present in many of our leases. To the extent these indices decline (All Commodities or the Iron and Steel subgroup),
royalty rates, and correspondingly royalty income, could be adversely affected. Conversely, higher producer price indices may
increase royalty rates and royalty income.
| | --------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------

6

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|Item 1A. |  | RISK FACTORS  Continued
|-------- |  | ------------------------

| | The loss of grantor trust status would have adverse tax
consequences. Compliance with Section 646 of the Internal Revenue Code is integral to the level of distributions paid to
the certificate holders. Should it be determined that we have violated the requirements of Section 646, the Trust would be taxed
as a corporation versus a grantor trust. This would mean our income would be taxable upon our receipt and again upon receipt by
the certificate holders. It is the Trustees opinion, based on independent tax firm reviews, that the Trust has remained in
compliance with the provisions of Section 646 since its election in 1988.
| | -------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------

|Item 1B. |  | UNRESOLVED STAFF COMMENTS
|-------- |  | -------------------------

| | None.
| | -----

|Item 2. |  | PROPERTIES
|------- |  | ----------

| | The Registrant owns interests in fee, both mineral and nonmineral
lands, on the Mesabi Iron Range of Minnesota, most of which are leased to mining companies that extract taconite. A list of the
leased properties is shown in table format in Item 1 above. The leases provide the lessees exclusive mining rights during the
term of such leases. Taconite deposits are substantial. The properties have a reversionary interest as explained in Item 1
above.
| | -----------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------

|Item 3. |  | LEGAL PROCEEDINGS
|------- |  | -----------------

| | In proceedings commenced in 1972, the Minnesota Supreme Court
determined that while by the terms of the Trust, the Trustees are given discretionary powers to convert Trust assets to cash and
to distribute the proceeds to certificate holders, they are limited in their exercise of those powers by the legal duty imposed by
well-established law of trusts to serve the interests of both term beneficiaries and the reversionary beneficiary with
impartiality. Thus, the Trustees have no duty to exercise the powers of sale and distribution unless required to do so to serve
both term and reversionary interests; and, if the need arises, the Trustees may petition the District Court of Ramsey County,
Minnesota, for further instructions defining what is required in a particular case to balance the interests of certificate holders
and reversioner. Also, the Court, in effect, held that the Trust is a conventional trust, rather than a business trust, and must
operate within the framework of well-established trust law.
| | ------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------

| | By a letter dated March 9, 2005, certificate holders of record as
of December 31, 2004, and the reversioner were notified of a Hearing on June 1, 2005, in Ramsey County Courthouse, Saint
Paul, Minnesota, for the purpose of settling and allowing the Trust accounts for the year 2004. By Court Order signed and dated
June 1, 2005, the 2004 accounts were settled and allowed in all respects. By previous Orders, the Court settled and allowed the
accounts of the Trustees for preceding years of the Trust.
| | ---------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------

7

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|Item 3. |  | LEGAL PROCEEDINGS  Continued
|------- |  | -----------------------------

| | By a letter dated September 1, 2005, certificate holders of record
as of June 30, 2005, and the reversioner were notified of a Hearing on October 19, 2005, in Ramsey County Courthouse, Saint Paul,
Minnesota, for the purpose of requesting increases in Trustee compensation. By Court Order signed and dated October 20, 2005, the
Court granted the requested fee increase of $10,000 per annum for each Trustee (including the President), effective July 1, 2005,
and, further, granted the requested potential bonus increase of $10,000 per annum for the President of the Trustees, effective for
the year 2005.
| | --------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------

|Item 4. |  | SUBMISSION OF MATTERS TO A VOTE OF CERTIFICATE HOLDERS
|------- |  | ------------------------------------------------------

| | None.
| | -----

PART II

|Item 5. |  | MARKET FOR THE REGISTRANTS SHARES OF BENEFICIAL INTEREST AND
RELATED SECURITY HOLDER MATTERS
|------- |  | ---------------------------------------------------------------------------------------------

| | Shares of Beneficial Interest, Market Prices and Distributions on
page 8 of the Annual Report to Certificate Holders for the year ended December 31, 2005, attached hereto as
Exhibit 13, are incorporated herein by reference.
| | -------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------

|Item 6. |  | SELECTED FINANCIAL DATA
|------- |  | -----------------------

| | Selected Financial Data (Summary of Operations) on page 2 of the
Annual Report to Certificate Holders for the year ended December 31, 2005, attached hereto as Exhibit 13, is incorporated herein
by reference.
| | ---------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------

|Item 7. |  | MANAGEMENTS DISCUSSION AND ANALYSIS OF FINANCIAL CONDITION AND RESULTS OF OPERATIONS
|------- |  | -------------------------------------------------------------------------------------

| | Trustees & Managements Discussion and Analysis of
Financial Condition and Results of Operations on pages 3, 4, 5 and 6 of the Annual Report to Certificate Holders for the year
ended December 31, 2005, attached hereto as Exhibit 13, are incorporated herein by reference.
| | -------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------

|Item 7A. |  | QUANTITATIVE AND QUALITATIVE DISCLOSURES ABOUT MARKET RISK
|-------- |  | ----------------------------------------------------------

| | None.
| | -----

8

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|Item 8. |  | FINANCIAL STATEMENTS AND SUPPLEMENTARY DATA
|------- |  | -------------------------------------------

| | The following financial statements of the Registrant are included
in the Annual Report to Certificate Holders for the year ended December 31, 2005, attached hereto as Exhibit 13, and are
incorporated herein by reference:
| | ----------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------

| | Balance Sheets  December 31, 2005 and 2004.
| | --------------------------------------------

| | Statements of Income  Years ended December 31, 2005, 2004
and 2003.
| | --------------------------------------------------------------------

| | Statements of Beneficiaries Equity  Years ended
December 31, 2005, 2004 and 2003.
| | -----------------------------------------------------------------------------------

| | Statements of Cash Flows  Years ended December 31, 2005,
2004 and 2003.
| | ------------------------------------------------------------------------

| | Notes to Financial Statements  December 31, 2005.
| | --------------------------------------------------

| | Quarterly Results of Operations on page 9 of the Annual Report to
Certificate Holders for the year ended December 31, 2005, attached hereto as Exhibit 13, are incorporated herein by reference.
| | ------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------

|Item 9. |  | CHANGES IN AND DISAGREEMENTS WITH ACCOUNTANTS ON ACCOUNTING AND FINANCIAL DISCLOSURE
|------- |  | ------------------------------------------------------------------------------------

| | None.
| | -----

|Item 9A. |  | CONTROLS AND PROCEDURES
|-------- |  | -----------------------

| | As of the end of the period covered by this report, the Trust
conducted an evaluation, under the supervision and with the participation of the Chief Executive Officer and Chief Financial
Officer, of the Trusts disclosure controls and procedures (as defined in Rules 13a-15(e) and 15d-15(e) under the Securities
Exchange Act of 1934 (the Exchange Act)). Based on this evaluation, the Chief Executive Officer and Chief Financial
Officer concluded that the Trusts disclosure controls and procedures are effective to ensure that information required to be
disclosed by the Trust in reports that it files or submits under the Exchange Act is recorded, processed, summarized and reported
within the time periods specified in Securities and Exchange Commission rules and forms.
| | ------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------

| | Managements Report On Internal Control Over Financial
Reporting on page 7 of the Annual Report to Certificate Holders for the year ended December 31, 2005, attached hereto as Exhibit
13, is incorporated herein by reference.
| | --------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------

9

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|Item 9A. |  | CONTROLS AND PROCEDURES  Continued
|-------- |  | -----------------------------------

| | The Report of Ernst & Young LLP, Independent Registered Public
Accounting Firm, on Managements Report On Internal Control Over Financial Reporting on pages 21 and 22 of the Annual Report
to Certificate Holders for the year ended December 31, 2005, attached hereto as Exhibit 13, is incorporated herein by reference.
| | ----------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------

| | There was no change in the Trusts internal control over
financial reporting during the Trusts most recently completed fiscal quarter that has materially affected, or is reasonably
likely to materially affect, the Trusts internal control over financial reporting (as defined in Rules 13a-15(f) and
15d-15(f) under the Exchange Act).
| | ----------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------

|Item 9B. |  | OTHER INFORMATION
|-------- |  | -----------------

| | None.
| | -----

PART III

|Item 10. |  | DIRECTORS AND EXECUTIVE OFFICERS OF THE REGISTRANT
|-------- |  | --------------------------------------------------

| | The Registrant, being a trust, has no directors as such. The
management of the Trust is vested in the following Trustees and officers whose terms of office are not fixed for a specified time:
| | -----------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------

|Name and Position    |  | Age                                                            |  | Years of Service inPosition
|-------------------- |  | -------------------------------------------------------------- |  | ---------------------------
|                     |  |                                                                |  |                            
|Joseph S. Micallef   |  | Trustee and President of the Trustees, Chief Executive Officer |  | 72                         
|Roger W. Staehle (1) |  | Independent Trustee                                            |  | 72                         
|Robert A. Stein (2)  |  | Independent Trustee                                            |  | 67                         
|John H. Roe, III (3) |  | Independent Trustee                                            |  | 66                         
|Thomas A. Janochoski |  | Vice President & Secretary, Chief Financial Officer            |  | 47                         

| | _________________
| | -----------------
| | (1)              
| | (2)              
| | (3)              

10

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|Item 10. |  | DIRECTORS AND EXECUTIVE OFFICERS OF THE REGISTRANT  Continued
|-------- |  | --------------------------------------------------------------

| | The Board of Trustees meets quarterly throughout the year. The
principal occupations of the Trustees and officers during the last five years were as follows:
| | -------------------------------------------------------------------------------------------------------------------------------------------------------------

| | JOSEPH S. MICALLEF
| | ------------------

| | President of the Trustees and Chief Executive Officer, Great
Northern Iron Ore Properties.
| | ------------------------------------------------------------------------------------------

| | ROGER W. STAEHLE
| | ----------------

| | Adjunct Professor, Institute of Technology, University of
Minnesota; Industrial Consultant.
| | -------------------------------------------------------------------------------------------

| | ROBERT A. STEIN
| | ---------------

| | Executive Director and Chief Operating Officer, American Bar
Association.
| | -------------------------------------------------------------------------

| | JOHN H. ROE, III
| | ----------------

| | Chairman of the Board, Bemis Company, Inc., Minneapolis, Minnesota
until May 5, 2005.
| | -------------------------------------------------------------------------------------

| | THOMAS A. JANOCHOSKI
| | --------------------

| | Vice President & Secretary, Chief Financial Officer, Great
Northern Iron Ore Properties.
| | ----------------------------------------------------------------------------------------

| | Executive employees in addition to those listed above include
Roger P. Johnson, Manager of Mines and Chief Engineer.
| | --------------------------------------------------------------------------------------------------------------------

| | There are no family relationships among any of the above persons.
| | -----------------------------------------------------------------

|Item 11. |  | EXECUTIVE COMPENSATION
|-------- |  | ----------------------

| | Summary Compensation Table
| | --------------------------

|Name andPrincipal Position      |  | Year |      |  | Salary |   | Bonus   |  | All OtherCompensation
|------------------------------- |  | ---- | ---- |  | ------ | - | ------- |  | ---------------------
|CEO/President of the Trustees:  |  |      |      |  |        |   |         |  |                      
|Joseph S. Micallef              |  |      | 2005 |  |        | $ | 155,000 |  | $                    
|                                |  |      | 2004 |  |        |   | 150,000 |  |                      
|                                |  |      | 2003 |  |        |   | 150,000 |  |                      
|                               
|CFO/Vice President & Secretary: |  |     
|Thomas A. Janochoski            |  |      | 2005 |  |        | $ | 129,667 |  | $                    
|                                |  |      | 2004 |  |        |   | 123,133 |  |                      
|                                |  |      | 2003 |  |        |   | 113,433 |  |                      

11

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|Item 11. |  | EXECUTIVE COMPENSATION  Continued
|-------- |  | ----------------------------------

| | Chief Executive Officer (CEO)/President of the Trustees
Compensation
| | --------------------------------------------------------------------

| | The Trust Agreement (as modified by Court Orders, the last being
effective July 1, 2005) provides for annual compensation to the CEO/President of the Trustees of $160,000 and, in addition, a
sum equal to 1% of the excess of gross income of the Trust over $5,000,000 for that year until his total compensation shall reach
$220,000. By Court Orders previous to 2005, annual compensation to the CEO/President of the Trustees for the years 2004 and 2003
was set at $150,000 and, in addition, a sum equal to 1% of the excess of gross income of the Trust over $5,000,000 for that year
until his total compensation shall reach $200,000.
| | -----------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------

| | Trustee Compensation (Other Than the CEO/President of the
Trustees)
| | -------------------------------------------------------------------

| | The Trust Agreement (as modified by Court Orders, the last being
effective July 1, 2005) provides for annual compensation to each Trustee (other than the CEO/President of the Trustees) of
$60,000. By Court Orders previous to 2005, annual compensation to each Trustee (other than the CEO/President of the Trustees) for
the years 2004 and 2003 was set at $50,000.
| | -------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------

| | Because the compensation of the Trustees and CEO/President of the
Trustees is established by the Trust Agreement (as modified by Court Orders), there is no compensation committee for the Trustees
and, accordingly, there is no Trustee compensation committee report pertaining to their compensation, nor is there a performance
graph generated to link total return to executive compensation. There are no other arrangements pursuant to which any Trustee was
compensated for any services provided as a Trustee, including that of committee participation or special assignment. There are no
options, stock appreciation rights, long-term performance-based incentive plans or retirement benefits applicable to any of the
Trustees (including the CEO/President of the Trustees) and, accordingly, disclosure tables with respect to such items have been
omitted.
| | ---------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------

| | Executive Officer Compensation of the Chief Financial Officer
(CFO)/Vice President & Secretary
| | ----------------------------------------------------------------------------------------------

| | The Board of Trustees, as a whole, determines compensation of
executive officers (other than the CEO/President of the Trustees). No compensation committee report exists, as the Trust Agreement
empowers and grants the Trustees authority to establish salaries for all employees of the Trust. The Trustees base employee salary
compensation on market data obtained from time to time, as deemed necessary. The CFOs Bonus compensation is based on 10% of
the CEO/Presidents Bonus compensation. All Other Compensation of the CFO represents an accrual and interest earnings
established in a deferred compensation plan.
| | -----------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------

12

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|Item 11. |  | EXECUTIVE COMPENSATION  Continued
|-------- |  | ----------------------------------

| | The following table shows the CFOs estimated annual pension
benefit payable upon retirement at various years of vested service as indicated:
| | ---------------------------------------------------------------------------------------------------------------------------------------------

| | Pension Plan Table
| | ------------------

|Average AnnualSalary for Highest60 Months ofConsecutive Service |         | Estimated Annual Pension Benefit Payablefor Years of Vested Service Indicated
|--------------------------------------------------------------- | ------- | -----------------------------------------------------------------------------
|
|$                                                               | 110,000 |                                                                              
|                                                                | 120,000 |                                                                              
|                                                                | 130,000 |                                                                              
|                                                                | 140,000 |                                                                              
|                                                                | 150,000 |                                                                              
|                                                                | 160,000 |                                                                              
|                                                                | 170,000 |                                                                              
|                                                                | 180,000 |                                                                              
|                                                                | 190,000 |                                                                              

| | The CFOs estimated annual pension benefit payable upon
retirement from the Trusts defined benefit Pension Plan is based on the highest 60 consecutive months average annual salary
as disclosed in the Summary Compensation Table above, the years of vested service, a straight-life annuity and no offsets or
deductions. The CFO is presently entitled to 16 years of vested service as of December 31, 2005. Upon the Trust termination on
April 6, 2015, the CFO would be entitled to 25 years of vested service.
| | ------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------

|Item 12. |  | SECURITY OWNERSHIP OF CERTAIN BENEFICIAL OWNERS AND MANAGEMENT
|-------- |  | --------------------------------------------------------------

| |  | (a) |  | The only authorized securities of the Registrant are
Trustees Certificates of Beneficial Interest. These securities are traded on the New York Stock Exchange under the ticker
symbol GNI (CUSIP No. 391064102). The holders of these securities do not have voting rights. There were no entities
holding more than 5% of the Certificates of Beneficial Interest outstanding, of record and/or beneficially, as of December 31,
2005.
| |  | --- |  | ------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------

| |  | (b) |  | There were no securities owned by the Trustees or officers as of
December 31, 2005.
| |  | --- |  | -----------------------------------------------------------------------------------

|Item 13. |  | CERTAIN RELATIONSHIPS AND RELATED TRANSACTIONS
|-------- |  | ----------------------------------------------

| | None.
| | -----

13

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|Item 14. |  | PRINCIPAL ACCOUNTANT FEES AND SERVICES
|-------- |  | --------------------------------------

| | All audit and non-audit services (printing and reproduction
services) were preapproved by the Audit Committee. Estimated fees in 2005 for the annual audit services are $67,700, for
audited-related services are $1,300, for tax services are $0 and for all other services are $2,750. Fees paid in 2004 for the
annual audit services were $79,250, for audit-related services were $1,300, for tax services were $0 and for all other services
were $2,750.
| | ---------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------

PART IV

|Item 15. |  | EXHIBITS, FINANCIAL STATEMENT SCHEDULES AND REPORTS ON FORM 8-K
|-------- |  | ---------------------------------------------------------------

| |  | (a) | (1) |  | The following financial statements of Great Northern Iron Ore
Properties are included in the Registrants Annual Report to Certificate Holders for the year ended December 31, 2005,
attached hereto as Exhibit 13, and are incorporated by reference in Item 8:
| |  | --- | --- |  | ----------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------

| | Balance Sheets  December 31, 2005 and 2004.
| | --------------------------------------------

| | Statements of Income  Years ended December 31, 2005, 2004
and 2003.
| | --------------------------------------------------------------------

| | Statements of Beneficiaries Equity  Years ended
December 31, 2005, 2004 and 2003.
| | -----------------------------------------------------------------------------------

| | Statements of Cash Flows  Years ended December 31, 2005,
2004 and 2003.
| | ------------------------------------------------------------------------

| | Notes to Financial Statements  December 31, 2005.
| | --------------------------------------------------

| |  |  | (2) |  | All Item 15(c) schedules for which provision is made in the
applicable accounting regulation of the SEC are not required under the related instructions or are inapplicable and therefore have
been omitted.
| |  |  | --- |  | ------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------

| |  |  | (3) |  | Listing of Exhibits  See the Exhibit Index
immediately following the signature page.
| |  |  | --- |  | ---------------------------------------------------------------------------------------

| |  | (b) |  | Exhibits  The response to this portion of Item 15 is set
forth above in Item 15(a)(3) of this report.
| |  | --- |  | ------------------------------------------------------------------------------------------------------

| |  | (c) |  | Financial Statement Schedules  The response to this portion
of Item 15 is set forth above in Item 15(a)(2) of this report.
| |  | --- |  | ---------------------------------------------------------------------------------------------------------------------------

14

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SIGNATURES

Pursuant to the requirements of Section 13 or 15(d) of the Securities
Exchange Act of 1934, the Registrant has duly caused this report to be signed on its behalf by the undersigned, thereunto duly
authorized.

GREAT NORTHERN IRON ORE PROPERTIES(Registrant)

|                                                                                    
|------------------------------------------------------------------------------------
|                                                                                    
|/s/   Joseph S. Micallef                                                            
|                                                                                    
|Joseph S. Micallef, Chief Executive Officer,   Trustee and President of the Trustees

Pursuant to the requirements of the Securities Exchange Act of 1934, this
report has been signed below by the following persons on behalf of the Registrant and in the capacities and on the dates
indicated.

|/s/   Roger W. Staehle                 |  | February 16, 2006 | 
|-------------------------------------- |  | ----------------- | 
|                                       |  |                   | 
|Roger W. Staehle, Trustee              |  | Date              | 
|                                      
|                                      
|/s/   Robert A. Stein                  |  | February 16, 2006 | 
|                                       |  |                   | 
|Robert A. Stein, Trustee               |  | Date              | 
|                                      
|                                      
|/s/   John H. Roe, III                 |  | February 16, 2006 | 
|                                       |  |                   | 
|John H. Roe, III, Trustee              |  | Date              | 
|                                      
|                                      
|/s/   Thomas A. Janochoski             |  | February 16, 2006 | 
|                                       |  |                   | 
|Thomas A. Janochoski, Vice President & |  | Date              | 
|Secretary, Chief Financial Officer     | 

15

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ANNUAL REPORT ON FORM 10-K

EXHIBIT INDEX

YEAR ENDED DECEMBER 31, 2005

GREAT NORTHERN IRON ORE PROPERTIES

W-1290 First National Bank Building 
332 Minnesota Street 
Saint Paul, Minnesota 55101-1361

Exhibit 3  Copy of Trust Agreement and Rules and Regulations for
Management of the Trust (filed as Exhibit A to Form 11 of Great Northern Iron Ore Properties filed on May 6, 1935, as
published under date of March 30, 1935, and incorporated by reference)

Exhibit 4  Specimen of Securities Registered Hereunder (filed as
Exhibit E to Form 11 of Great Northern Iron Ore Properties filed on May 6, 1935, as published under date of March 30, 1935,
and incorporated by reference)

Exhibit 10  Court Order on Trustee Compensation dated October 20, 2005

Exhibit 13  Annual Report to Certificate Holders

Exhibit 23  Consent of Independent Registered Public
Accounting Firm

Exhibit 31.1  Certification of Chief Executive Officer pursuant to
Section 302 of the Sarbanes-Oxley Act of 2002

Exhibit 31.2  Certification of Chief Financial Officer pursuant to
Section 302 of the Sarbanes-Oxley Act of 2002

Exhibit 32  Certifications of Chief Executive Officer and Chief
Financial Officer pursuant to Section 906 of the Sarbanes-Oxley Act of 2002 (furnished but not filed)

Exhibit 99(a)  Tax Return Guide

Exhibit 99(b)  Audit Committee Charter

Exhibit 99(c)  Report of Audit Committee

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