Exhibit 10.1

TWENTY-THIRD AMENDMENT
TO
SECOND AMENDED AND RESTATED
LIMITED PARTNERSHIP AGREEMENT
OF
CORPORATE OFFICE PROPERTIES, L.P.

This Twenty-Third Amendment (the Amendment) to the Second Amended and Restated
Limited Partnership Agreement Of Corporate Office Properties, L.P., a Delaware
limited partnership (the Partnership), is made and entered into as of April 6,
2007, by the undersigned.

RECITALS

A.            The Partnership is a limited partnership organized under the
Delaware Revised Uniform Limited Partnership Act and governed by that certain
Second Amended and Restated Limited Partnership Agreement dated as of December
7, 1999, as amended to the date hereof (as amended, the “Partnership
Agreement”).

B.            The sole general partner of the Partnership is Corporate Office
Properties Trust, a real estate investment trust formed under the laws of the
State of Maryland (the “General Partner”).

C.            Pursuant to Section 11.1 (b) (iii), the General Partner desires to
amend the Partnership Agreement to reflect the admission, substitution,
termination and/or withdrawal of various limited partners in accordance with the
terms of the Partnership Agreement.

NOW THEREFORE, the General Partner, intending to be legally bound, hereby amends
the Partnership Agreement as follows, effective as of the date first set forth
above.

1.                                       Exhibit 1, Schedule of Partners, as
attached hereto and by this reference made a part hereof, is hereby substituted
for and intended to replace any prior Exhibit 1 attached to a prior Amendment to
the Partnership Agreement, and as attached hereto shall be a full and complete
listing of all the general and limited partners of the Partnership as of the
date of this Amendment, same being intended and hereby superceding all prior
Exhibit 1 listings.

In Witness Whereof, the General Partner has executed this Amendment as of the
day and year first above written.

Corporate Office Properties Trust, a

 

Maryland Real Estate Investment Trust

 

 

 

 

 

By:

/s/ RANDALL M. GRIFFIN

 

 

 

Randall M. Griffin

 

 

 

President and Chief Executive Officer

 

 

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Exhibit 1 Addendum

Schedule of Partners

General Partner

 

 

 

Common
Units of 
Partnership 
Units

 

Series G
Preferred 
Units

 

Series H
Preferred
Units

 

Series I
Preferred
Units

 

Series J
Preferred
Units

 

Series K
Preferred
Units

 

Corporate Office Properties Trust

 

44,938,069

 

2,200,000

 

2,000,000

 

 

 

3,390,000

 

531,667

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

Limited Partners and Preferred Limited Partners

 

 

 

 

 

 

 

 

 

 

 

 

 

Jay H. Shidler

 

452,878

 

 

 

 

 

 

 

 

 

 

 

Shidler Equities, L.P.

 

2,995,439

 

 

 

 

 

 

 

 

 

 

 

Clay W. Hamlin, III

 

489,917

 

 

 

 

 

 

 

 

 

 

 

LBCW Limited Partnership

 

2,681,107

 

 

 

 

 

 

 

 

 

 

 

Robert L. Denton

 

400,000

 

 

 

 

 

 

 

 

 

 

 

James K. Davis

 

51,589

 

 

 

 

 

 

 

 

 

 

 

John E. De B. Blockey, Trustee of the John E. de B. Blockey Living Trust dated
9/12/88

 

300,625

 

 

 

 

 

 

 

 

 

 

 

Frederick K. Ito Trust

 

20,340

 

 

 

 

 

 

 

 

 

 

 

June Y. I. Ito Trust

 

20,335

 

 

 

 

 

 

 

 

 

 

 

RP Investments, LLC

 

100,000

 

 

 

 

 

 

 

 

 

 

 

Denise J. Liszewski

 

23,333

 

 

 

 

 

 

 

 

 

 

 

Samuel Tang

 

4,389

 

 

 

 

 

 

 

 

 

 

 

Lawrence J. Taff

 

13,733

 

 

 

 

 

 

 

 

 

 

 

Kimberly F. Aquino

 

2,937

 

 

 

 

 

 

 

 

 

 

 

M.O.R. XXIX Associates Limited Partnership

 

148,381

 

 

 

 

 

 

 

 

 

 

 

M.O.R. 44 Gateway Associates Limited Partnership

 

1

 

 

 

 

 

 

 

 

 

 

 

John Parsinen

 

49,434

 

 

 

 

 

 

 

 

 

 

 

M.O.R. Commons Limited Partnership

 

7

 

 

 

 

 

 

 

 

 

 

 

John Edward De Burgh Blockey and Sanda Juanita Blockey

 

10,476

 

 

 

 

 

 

 

 

 

 

 

Lynn Hamlin

 

121,411

 

 

 

 

 

 

 

 

 

 

 

Housing Affiliates, Inc.

 

4,402

 

 

 

 

 

 

 

 

 

 

 

Reingle Corp.

 

730

 

 

 

 

 

 

 

 

 

 

 

Joseph Tawil

 

2,160

 

 

 

 

 

 

 

 

 

 

 

The Lovejoy Trust

 

59,528

 

 

 

 

 

 

 

 

 

 

 

The Century Trust

 

59,528

 

 

 

 

 

 

 

 

 

 

 

A. Charles Wilson & Betty S. Wilson Trust

 

5,908

 

 

 

 

 

 

 

 

 

 

 

Harold & Renee Holland

 

4,320

 

 

 

 

 

 

 

 

 

 

 

Irwin Hoffman

 

1,880

 

 

 

 

 

 

 

 

 

 

 

Rouse 1988 Trust

 

2,160

 

 

 

 

 

 

 

 

 

 

 

CB Management, L.L.C.

 

2,497

 

 

 

 

 

 

 

 

 

 

 

Patriot Partner, L.L.C.

 

25,000

 

 

 

 

 

 

 

 

 

 

 

National Prostate Cancer Coalition

 

400

 

 

 

 

 

 

 

 

 

 

 

John A. Luetkemeyer, Jr.

 

38,954

 

 

 

 

 

 

 

 

 

 

 

Lawrence G. Rief

 

2,526

 

 

 

 

 

 

 

 

 

 

 

Arthur Ashe Youth Tennis & Education

 

300

 

 

 

 

 

 

 

 

 

 

 

Heritage Foundation

 

200

 

 

 

 

 

 

 

 

 

 

 

Volunteers in Medicine

 

500

 

 

 

 

 

 

 

 

 

 

 

David D. Jenkins

 

262,165

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

TRC Associates Limited Partnership

 

 

 

 

 

 

 

352,000

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

53,297,559

 

2,200,000

 

2,000,000

 

352,000

 

3,390,000

 

531,667

 

 

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