The United States Mint in Washington, D.C., is a division of the U.S. Department of the Treasury. It is the headquarters for the U.S. Mint s operations and is responsible for policy formulation and central agency administration; program management; research and development; marketing operations; customer services and order processing; operation of the Union Station sales center; and business unit management. The U.S. Mint has production and engraving facilities in Philadelphia, Denver, San Francisco and West Point, N.Y. The U.S. gold bullion depository is in Fort Knox, Ky. The primary mission of the United States Mint is to produce an adequate volume of circulating coinage for the nation to conduct its trade and commerce. In recent history circulating coin production has varied between 11 billion and 20 billion coins annually.