National Women's History Museum Act of 2011

National Women's History Museum Act of 2011 - (Sec. 3) Directs the Administrator of General Services (GSA) to convey, by quitclaim deed, to the National Women's History Museum, Inc. (the Museum) specified property (commonly known as the "Cotton Annex" site) in the District of Columbia, on terms which the Administrator deems appropriate.

Requires the purchase price for the property to be: (1) its market value based on its highest and best use, as determined by an independent appraisal performed under the assumption that the property does not contain any hazardous substances, waste, or pollutants requiring a response under applicable environmental laws; and (2) paid into the Federal Buildings Fund.

Requires the property to be dedicated for use as a site for a national women's history museum for a 99-year period.

Prohibits using federal funds to purchase the property or design and construct any facility on such property.

Provides for the reversion of the property to the United States without any obligation for repayment of any amount of the purchase price if: (1) it is not used as a site for a national women's history museum during the 99-year period, and (2) the Museum has not commenced construction of a museum facility on such property in a 5-year period other than for reasons beyond the Museum's control.

(Sec. 4) Authorizes the Administrator to contract with the Museum (or an affiliate) to address any contamination on the property. Directs any nonfederal funds used by the Museum on the Administrator's behalf in response to any such contamination to be credited to the purchase price of the property.

Prohibits: (1) the availability of federal funds for such a credit, and (2) any credit from exceeding the purchase price.

(Sec. 5) Directs the Museum to bear any costs of complying with this Act (subject to the Administrator's responsibility to address any contamination), including studies, reports, surveys, relocating tenants, and mitigating impacts to existing federal buildings and structures.

(Sec. 6) Sets forth the responsibilities of the Administrator with respect to any zoning or land use matters relating to the Museum's development.

(Sec. 7) Requires, for a five-year period or until substantial completion of the museum facility (whichever is later), an annual report to Congress and the Administrator detailing development and construction activities.