Wash. Rev. Code § 36.34.260
In any county where the federal government owns and maintains property under the jurisdiction of the navy department or war department, or any other federal department, the board of county commissioners by majority vote may sell, lease or transfer to the United States government any real or personal property owned by said county, however acquired, for the use and benefit of any branch of the army, navy, marine corps or air forces thereof or for enlarging or improving any military base thereof, or for any other governmental housing project, or to the state of Washington, without requiring competitive bids or notice to the public and at such price and terms as the board may deem for the best interests of the county. This property may be conveyed to the government of the United States by bill of sale or other instrument of conveyance and need not require consideration other than the benefit which may be derived by the county on account of the use thereof and development of such property by the United States government. The state of Washington may buy and/or sell such property, or the state of Washington may buy and/or sell such property for the purposes herein stated; or mutually interchange or trade such property or purchase one from the other.
RCW 36.34.260