The Seventh Fleet is a numbered fleet of the United States Navy. It is headquartered at U.S. Fleet Activities Yokosuka, in Yokosuka, Kanagawa Prefecture, Japan. It is part of the United States Pacific Fleet. At present, it is the largest of the forward-deployed U.S. fleets, with 50 to 70 ships, 150 aircraft and 27,000 sailors and marines. Its principal responsibilities are to provide joint command in natural disaster or military operations and operational command of all U.S. naval forces in the region.