As filed with the Securities and Exchange Commission on November 22, 2005

                                                     Registration No. 333-122243
================================================================================

                       SECURITIES AND EXCHANGE COMMISSION
                             WASHINGTON, D.C. 20549

                                 ---------------

                                    FORM S-4

                         POST EFFECTIVE AMENDMENT NO. 1

                                       TO

                             REGISTRATION STATEMENT

                                      UNDER

                           THE SECURITIES ACT OF 1933

                                 ---------------

                              GLACIER BANCORP, INC.
             (Exact name of registrant as specified in its charter)



                                                                     

              MONTANA                               6022                      81-0579541
  (State or other jurisdiction of       (Primary standard industrial      (I.R.S. employer 
   incorporation or organization)        classification code number)     identification no.)



            49 COMMONS LOOP, KALISPELL, MONTANA 59901 (406) 756-4200
               (Address, including zip code, and telephone number,
       including area code, of registrant's principal executive offices)

                                   ----------

                               MICHAEL J. BLODNICK
                      President and Chief Executive Officer
                                 49 Commons Loop
                            Kalispell, Montana 59901
                                 (406) 756-4200

            (Name, address, including zip code, and telephone number,
                   including area code, of agent for service)

                                   -----------

                          Copies of communications to:

                            KIMBERLY F. STEPHAN, ESQ.
                             BART E. BARTHOLDT, ESQ.
                               Graham & Dunn P.C.
                      Pier 70, 2801 Alaskan Way, Suite 300
                            Seattle, Washington 98121






                     DEREGISTRATION OF UNISSUED SECURITIES

     The Registration Statement of Glacier Bancorp, Inc. ("Glacier") on Form S-4
declared effective on February 15, 2005, Commission File No. 333-122243 (the
"Registration Statement"), provided for the issuance of up to 323,584 shares of
Glacier's common stock.

     These securities were registered for issuance in accordance with the Plan
and Agreement of Merger to acquire Citizens Bank Holding Company dated 
December 15, 2004, (the "Agreement") described in the Registration Statement. 
Pursuant to the exchange formula in the Agreement and unexercised stock options,
282,750 shares of Glacier's common stock were exchanged, leaving 40,834 shares
registered but unissued. No further securities are to be exchanged pursuant to
the Agreement. Accordingly, Glacier hereby deregisters 40,834 shares not
exchanged pursuant to the Agreement.


                                   SIGNATURES

     Pursuant to the requirements of the Securities Act of 1933, the registrant
has duly caused this Post-Effective Amendment No. 1 to this Registration
Statement to be signed on its behalf by the undersigned, thereunto duly
authorized, in the City of Kalispell, State of Montana, on November 21, 2005.



                                         GLACIER BANCORP, INC.
                                               (Issuer)




                                         By:  /s/ Michael J. Blodnick
                                              ---------------------------------
                                              Michael J. Blodnick
                                              President and Chief Executive
                                              Officer





     Pursuant to the requirements of the Securities Act of 1933, this Post
Effective Amendment No. 1 to the registration statement has been signed by the
following persons in the capacities indicated on this 21 day of November 2005.



               SIGNATURE                                 TITLE
               ---------                                 -----

PRINCIPAL EXECUTIVE OFFICER


    /s/ Michael J. Blodnick                       President and Chief
-----------------------------------               Executive Officer, Director
Michael J. Blodnick                                       



PRINCIPAL FINANCIAL OFFICER


   /s/ James H. Strosahl                          Executive Vice President and
-----------------------------------               Chief Financial Officer 
James H. Strosahl                                 (Principal Accounting Officer)
                                                          


*  A Majority of the Board of Directors


John S. MacMillan
William L. Bouchee
James M. English
Jon W. Hippler
L. Peter Larson
Everit A Sliter



*By:    /s/ Michael J. Blodnick
     -------------------------------
     Michael J. Blodnick
     (Attorney-in-Fact and Designated 
     Agent for Service)