Issuer Free Writing Prospectus
Filed Pursuant to Rule 433
Dated November 13, 2008
Registration Statement No. 333-154968

GLACIER BANCORP, INC.

5,500,000 Shares
Common Stock

Issuer:

Glacier Bancorp, Inc.

Change in Offering Size:

The contemplated offering size has been changed from an aggregate of 4,000,000 shares to 5,500,000 shares of the Issuer’s Common Stock, par value $0.01 per share, and the 30-day option granted to the underwriters to purchase up to an additional 600,000 shares to cover over-allotments has been changed to 825,000 shares. The change in the offering size will be reflected at the appropriate places in the Prospectus Supplement to the Prospectus dated November 3, 2008 (Registration Statement No. 333-154968), which Prospectus Supplement will be filed by the Issuer pursuant to Rule 424.

The issuer has filed a registration statement (including a prospectus) with the SEC for the offering to which this communication relates. Before you invest, you should read the prospectus in that registration statement and other documents the issuer has filed with the SEC for more complete information about the issuer and this offering. You may get these documents for free by visiting EDGAR on the SEC Web site at www.sec.gov. Alternatively, the issuer, any underwriter or any dealer participating in the offering will arrange to send you the prospectus if you request it by contacting D.A. Davidson & Co. — Prospectus Department, 8 Third Street North, Great Falls, MT 59401, 800-332-5915.

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