It was established as a defense of Washington, D.C. along the Potomac River in Maryland. This was originally called Fort Warburton, which was abandoned by Americans during the War of 1812 as the British were coming up the Potomac with a large naval force. They stopped in front of the fort, found it abandoned, then destroyed it. It was rebuilt and designated as Fort Washington. Named after the first President of the United States, who also lived just down the Potomac on from the fort on the Virginia side.
