Alternative Titles: Revenue Cutter Service, Revenue Marine Service, USCG
United States Coast Guard (USCG) , military service within the U.S. armed forces that is charged with the enforcement of maritime laws. It consists of approximately 35,000 officers and enlisted personnel, in addition to civilians. It is under the jurisdiction of the Department of Homeland Security. In time of war, it functions as part of the U.S. Navy and is under the direction of the president.