USS Mercury (ID-3012) was a United States Navy transport ship during World War I. She was formerly the Norddeutscher Lloyd liner SS Barbarossa built by Blohm & Voss, Hamburg, Germany, in 1897, and operated by the North German Lloyd Line. At the outset of World War I the ship was interned by the United States and, when that country entered the conflict in 1917, was seized and converted to a troop transport. After decommissioning by the U.S. Navy, the ship was turned over to the Army Transport Service and then to the U.S. Shipping Board. She was sold for scrapping in February 1924.