Fort Ellsworth was a timber and earthwork fortification constructed west of Alexandria, Virginia, as part of the defenses of Washington, D.C. during the American Civil War. Built in the weeks following the Union defeat at Bull Run, Fort Ellsworth was situated on a hill north of Hunting Creek, and Cameron Run, (which feeds into it). From its position on one of the highest points west of Alexandria, the fort overlooked the Orange and Alexandria Railroad, the Little River Turnpike, and the southern approaches to the city of Alexandria, the largest settlement in Union-occupied Northern Virginia.