The fort was constructed as a part of a defensive ring around Washington. Following the Union defeat at Bull Run, Congress voted to augment the city's defenses, which consisted of a single fort (Fort Washington) twelve miles to the south on the Potomac. (Eventually, "68 forts, 93 batteries, 20 miles of rifle pits, and 32 miles of military roads surrounded the capital and Washington became the most heavily fortified city in the world.")