Wash. Rev. Code § 36.34.250
The board of county commissioners of any county by a majority vote are hereby authorized to directly lease, sell, or convey by gift, all or any portion of real estate, or any interest therein owned by the county, however acquired, by tax foreclosure or in any other manner, to the United States for the use and benefit of any branch of the army, navy, marine corps or air forces of the United States, or for enlarging or improving any military base thereof, or for any governmental housing project, or for the purpose of constructing and operating any federal power 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. The property may be conveyed to the United States or to the state of Washington by deed or other instrument of conveyance and shall not require any consideration, if donated, 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 or the state.
RCW 36.34.250