**UNITED
      STATES**




**SECURITIES
      AND EXCHANGE COMMISSION**




**WASHINGTON,
      D.C. 20549**




**FORM
      8-K**




**CURRENT
      REPORT**




**Pursuant
      to Section 13 or 15(d) of the**


**Securities
      Exchange Act of 1934**





Date
      of
      report: **December
      5, 2006**


(Date
      of
      earliest event reported)







**NORTHERN
      ILLINOIS GAS COMPANY**


**(Doing
      Business as NICOR GAS COMPANY)** **.**




(Exact
      name of registrant as specified in its charter)




**Illinois**
            **1-7297**
            **36-2855175**(State
                of
            (Commission
                File Number)
            (IRS
                EmployerIncorporation)
            
            Identification
                No.)


**1844
      Ferry Road**


**Naperville,
      Illinois 60563-9600**


(Address
      of principal executive offices, including zip code)




**(630)
      983-8888**


(Registrant’s
      telephone number, including area code)







Check
      the
      appropriate box if the Form 8-K filing is intended to simultaneously satisfy
      the
      filing obligation of the registrant under any of the following
      provisions:




[
      ]  Written
      communications pursuant to Rule 425 under the Securities Act (17 CFR
      230.425)




[
      ]  Soliciting
      material pursuant to Rule 14a-12 under the Exchange Act (17 CFR
      240.14a-12)




[
      ]  Pre-commencement
      communications pursuant to Rule 14d-2(b) under the Exchange Act (17 CFR
      240.14d-2(b))




[
      ]  Pre-commencement
      communications pursuant to Rule 13e-4(c) under the Exchange Act (17 CFR
      240.13e-4(c))












**Page
      1**




**Item
      7.01**  **Regulation
      FD Disclosure**




On
      December 5, 2006, Nicor Inc. (the “Company”) issued a press release announcing
      that it has been advised by the Office of the United States Attorney for the
      Northern District of Illinois (the “U.S. Attorney”) that it is closing its
      inquiry and will not seek to prosecute the Company or any individuals in
      connection with Nicor Gas’ former Performance-Based Rate (PBR) plan. As
      previously disclosed, in 2002 the U.S. Attorney issued a notification of inquiry
      related to the Company’s actions in connection with the accounting for natural
      gas costs pursuant to the PBR plan.




Information
      in this Item is furnished to, but not filed with, the Securities and Exchange
      Commission solely under Item 7.01 of Form 8-K, “Regulation FD
      Disclosure.”




A
      copy of
      the press release is furnished as Exhibit 99.1 to this Current Report on Form
      8-K and is incorporated herein by reference.









**Item
      9.01**  **Financial
      Statements and Exhibits.**




(d)  Exhibits




Exhibit
      No .  Description




99.1   Press
      release dated December 5, 2006







**Page
      2**









**SIGNATURE**




Pursuant
      to the requirements of the Securities Exchange Act of 1934, the registrant
      has
      duly caused this report to be signed on its behalf by the undersigned hereunto
      duly authorized.









Northern
      Illinois Gas Company








Dated:
      December 5, 2006    By:  /s/
      PAUL C. GRACEY, JR. ________________


Paul
      C. Gracey,
      Jr.


Senior
      Vice
      President, General Counsel and Secretary














**Page
      3**





**Exhibit
      Index**




Exhibit


Number   Description
      of Document




99.1     Press
      release
      of Nicor Inc. issued December 5, 2006