Why the Forts Were Built
After the Confederate bombardment and the surrender of Fort Sumter on April 12, 1861, Washington, DC was in a state of near panic. It found itself full of Southern sympathizers and surrounded by slave states. There was bold talk in Dixie of taking Maryland and making Washington the capital of the Confederacy. Federal troops were assaulted by a violent mob in Baltimore on their way to defend Washington. Pro-Confederate Marylanders severed the rail and telegraph connections to the North. Capture of the Federal capital by forces of the fledgling Confederacy would have been a severe, if not fatal, blow to the Union cause. Even worse, Washington was practically undefended.
Union officials began to fortify the capital and its treasury against the feared invasion. By the end of the Civil War, the city was the most heavily fortified city in the world, bristling with 68 forts and artillery emplacements, more than 1,000 guns and mortars, and 20 miles of connecting roads, trench lines, and rifle pits. Constructing the Defenses of Washington was the greatest engineering project of the war.
Under the direction of the army's chief engineer, Colonel John G. Barnard, thousands of soldiers and civilian workers labored throughout the war to turn rural farm fields, orchards, and woodlands into an imposing system of connected defensive fortifications. After hostilities ceased in 1865, these installations were quickly dismantled and most of the land returned to civilian ownership. Little thought was given to memorializing the ground on which they stood.
Over the years, most of the fortifications that did remain disappeared, victims of rapid urban development, expanding suburbs, and governmental neglect.
Beginning in the 1890's, however, some individuals and veterans organizations began to advocate preserving parts of some of the forts in the Defenses of Washington. In 1901, a congressional commission issued a report on improving the park system of the District of Columbia that included a scenic drive connecting what was left of the forts that defended the city. Other reports and feasibility studies have appeared periodically. Heroic efforts of the National Park Service, local governments, preservation organizations, and concerned individuals have managed to preserve traces of this once-mighty ring of fortifications.
Within the present boundaries of the District of Columbia, including east of the Anacostia, there were 28 forts and 21 batteries. Forever lost, except to memory, are 17 of those forts and 11 batteries. Fortunately, all are not lost and there are remnants of 10 forts and 10 gun battery emplacements still visible today.
You can find them, provided you know where to look and what to look for.
The Civil War Defenses of Washington
Maintained by the National Park Service and Located within the Boundaries of the District of Columbia