Nicor Gas Company
                                                                      Form 10-K
                                                                  Exhibit 24.01

                                POWER OF ATTORNEY

The undersigned, a Director, Officer, or Director and Officer of Nicor Inc. and
Northern Illinois Gas Company (doing business as Nicor Gas Company), Illinois
corporations, hereby authorizes any officer of Nicor Inc. and each of them, to
execute in the name and on behalf of the undersigned as such Director, Officer,
or Director and Officer, the 2004 Annual Report on Form 10-K of Nicor Inc. and
Nicor Gas Company (and any amendments thereto) to be filed pursuant to the
Securities Exchange Act of 1934.

Date:  January 20, 2005

/s/ ROBERT M. BEAVERS, JR.
--------------------------
Robert M. Beavers, Jr.



                                POWER OF ATTORNEY

The undersigned, a Director, Officer, or Director and Officer of Nicor Inc. and
Northern Illinois Gas Company (doing business as Nicor Gas Company), Illinois
corporations, hereby authorizes any officer of Nicor Inc. and each of them, to
execute in the name and on behalf of the undersigned as such Director, Officer,
or Director and Officer, the 2004 Annual Report on Form 10-K of Nicor Inc. and
Nicor Gas Company (and any amendments thereto) to be filed pursuant to the
Securities Exchange Act of 1934.

Date:  January 20, 2005

/s/ BRUCE P. BICKNER
--------------------
Bruce P. Bickner



                                POWER OF ATTORNEY

The undersigned, a Director, Officer, or Director and Officer of Nicor Inc. and
Northern Illinois Gas Company (doing business as Nicor Gas Company), Illinois
corporations, hereby authorizes any officer of Nicor Inc. and each of them, to
execute in the name and on behalf of the undersigned as such Director, Officer,
or Director and Officer, the 2004 Annual Report on Form 10-K of Nicor Inc. and
Nicor Gas Company (and any amendments thereto) to be filed pursuant to the
Securities Exchange Act of 1934.

Date:  January 20, 2005

/s/ JOHN H. BIRDSALL, III
-------------------------
John H. Birdsall, III



                                POWER OF ATTORNEY

The undersigned, a Director, Officer, or Director and Officer of Nicor Inc. and
Northern Illinois Gas Company (doing business as Nicor Gas Company), Illinois
corporations, hereby authorizes any officer of Nicor Inc. and each of them, to
execute in the name and on behalf of the undersigned as such Director, Officer,
or Director and Officer, the 2004 Annual Report on Form 10-K of Nicor Inc. and
Nicor Gas Company (and any amendments thereto) to be filed pursuant to the
Securities Exchange Act of 1934.

Date:  January 20, 2005

/s/ THOMAS A. DONAHOE
---------------------
Thomas A. Donahoe



                                POWER OF ATTORNEY

The undersigned, a Director, Officer, or Director and Officer of Nicor Inc. and
Northern Illinois Gas Company (doing business as Nicor Gas Company), Illinois
corporations, hereby authorizes any officer of Nicor Inc. and each of them, to
execute in the name and on behalf of the undersigned as such Director, Officer,
or Director and Officer, the 2004 Annual Report on Form 10-K of Nicor Inc. and
Nicor Gas Company (and any amendments thereto) to be filed pursuant to the
Securities Exchange Act of 1934.

Date:  January 20, 2005

/s/ THOMAS L. FISHER
--------------------
Thomas L. Fisher



                                POWER OF ATTORNEY

The undersigned, a Director, Officer, or Director and Officer of Nicor Inc. and
Northern Illinois Gas Company (doing business as Nicor Gas Company), Illinois
corporations, hereby authorizes any officer of Nicor Inc. and each of them, to
execute in the name and on behalf of the undersigned as such Director, Officer,
or Director and Officer, the 2004 Annual Report on Form 10-K of Nicor Inc. and
Nicor Gas Company (and any amendments thereto) to be filed pursuant to the
Securities Exchange Act of 1934.

Date:  January 20, 2005

/s/ JOHN E. JONES
-----------------
John E. Jones



                                POWER OF ATTORNEY

The undersigned, a Director, Officer, or Director and Officer of Nicor Inc. and
Northern Illinois Gas Company (doing business as Nicor Gas Company), Illinois
corporations, hereby authorizes any officer of Nicor Inc. and each of them, to
execute in the name and on behalf of the undersigned as such Director, Officer,
or Director and Officer, the 2004 Annual Report on Form 10-K of Nicor Inc. and
Nicor Gas Company (and any amendments thereto) to be filed pursuant to the
Securities Exchange Act of 1934.

Date:  January 20, 2005

/s/ DENNIS J. KELLER
--------------------
Dennis J. Keller



                                POWER OF ATTORNEY

The undersigned, a Director, Officer, or Director and Officer of Nicor Inc. and
Northern Illinois Gas Company (doing business as Nicor Gas Company), Illinois
corporations, hereby authorizes any officer of Nicor Inc. and each of them, to
execute in the name and on behalf of the undersigned as such Director, Officer,
or Director and Officer, the 2004 Annual Report on Form 10-K of Nicor Inc. and
Nicor Gas Company (and any amendments thereto) to be filed pursuant to the
Securities Exchange Act of 1934.

Date:  February  7, 2005

 /s/ R. EDEN MARTIN
-------------------
R. Eden Martin



                                POWER OF ATTORNEY

The undersigned, a Director, Officer, or Director and Officer of Nicor Inc. and
Northern Illinois Gas Company (doing business as Nicor Gas Company), Illinois
corporations, hereby authorizes any officer of Nicor Inc. and each of them, to
execute in the name and on behalf of the undersigned as such Director, Officer,
or Director and Officer, the 2004 Annual Report on Form 10-K of Nicor Inc. and
Nicor Gas Company (and any amendments thereto) to be filed pursuant to the
Securities Exchange Act of 1934.

Date:  January 20, 2005

/s/ WILLIAM A. OSBORN
---------------------
William A. Osborn



                                POWER OF ATTORNEY

The undersigned, a Director, Officer, or Director and Officer of Nicor Inc. and
Northern Illinois Gas Company (doing business as Nicor Gas Company), Illinois
corporations, hereby authorizes any officer of Nicor Inc. and each of them, to
execute in the name and on behalf of the undersigned as such Director, Officer,
or Director and Officer, the 2004 Annual Report on Form 10-K of Nicor Inc. and
Nicor Gas Company (and any amendments thereto) to be filed pursuant to the
Securities Exchange Act of 1934.

Date:  January 20, 2005

/s/ JOHN RAU
------------
John Rau



                                POWER OF ATTORNEY

The undersigned, a Director, Officer, or Director and Officer of Nicor Inc. and
Northern Illinois Gas Company (doing business as Nicor Gas Company), Illinois
corporations, hereby authorizes any officer of Nicor Inc. and each of them, to
execute in the name and on behalf of the undersigned as such Director, Officer,
or Director and Officer, the 2004 Annual Report on Form 10-K of Nicor Inc. and
Nicor Gas Company (and any amendments thereto) to be filed pursuant to the
Securities Exchange Act of 1934.

Date:  January 20, 2005

/s/ JOHN F. RIORDAN
-------------------
John F. Riordan



                                POWER OF ATTORNEY

The undersigned, a Director, Officer, or Director and Officer of Nicor Inc. and
Northern Illinois Gas Company (doing business as Nicor Gas Company), Illinois
corporations, hereby authorizes any officer of Nicor Inc. and each of them, to
execute in the name and on behalf of the undersigned as such Director, Officer,
or Director and Officer, the 2004 Annual Report on Form 10-K of Nicor Inc. and
Nicor Gas Company (and any amendments thereto) to be filed pursuant to the
Securities Exchange Act of 1934.

Date:  January 20, 2005

/s/ RUSS M. STROBEL
-------------------
Russ M. Strobel



                                POWER OF ATTORNEY

The undersigned, a Director, Officer, or Director and Officer of Nicor Inc. and
Northern Illinois Gas Company (doing business as Nicor Gas Company), Illinois
corporations, hereby authorizes any officer of Nicor Inc. and each of them, to
execute in the name and on behalf of the undersigned as such Director, Officer,
or Director and Officer, the 2004 Annual Report on Form 10-K of Nicor Inc. and
Nicor Gas Company (and any amendments thereto) to be filed pursuant to the
Securities Exchange Act of 1934.

Date:  January 20, 2005

/s/ PATRICIA A. WIER
--------------------
Patricia A. Wier