A picket boat is a type of small naval craft. These are used for harbor patrol and other close inshore work, and have often been carried by larger warships as a ship's boat. They are usually 30 to 55 feet long.

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.