USS Wachusett – the first U.S. Navy ship to be so named – was a large (1,032-ton), Mohican-class steam sloop-of-war that served the United States Navy during the American Civil War. She was outfitted as a gunboat and used by the Navy as part of the Union blockade of the Confederate States of America.

The Potomac Flotilla, also called the Potomac Squadron, was a unit of the United States Navy created in the early days of the American Civil War to secure Union communications in the Chesapeake Bay, the Potomac River and their tributaries, and to disrupt Confederate communications and shipping there.