Fort Willard Park
After Virginia seceded from the Union on April 17, 1861 the District of Columbia was on the dangerous border between the divided states. Because of the city's importance, the Union Army immediately occupied Northern Virginia, which allowed troops to protect the city's bridges and the Aqueduct, the city's primary water source.
After Alexandria was seized in May 1861 orders were issued to begin construction on Forts Corcoran, Haggerty, Bennett, Runyon, and Ellsworth surrounding the city. After the Confederate Army's victory at the Battle of Manassas in July 1861, concern for the safety of the District of Columbia and Alexandria prompted plans for a complete fortification system for Washington.
Major General George B. McClellan placed Major John Gross Barnard, Corps of Engineers, in charge of the construction of defenses for Washington. By the end of 1861, Barnard and his engineers had worked together with soldiers and civilians to complete 48 forts surrounding the city.
As the war progressed, military strategists recommended additional forts to be built to fill in gaps in the defensive system. The construction of Forts Whipple, Berry, C.F. Smith, and the redoubts to Fort Lyon provided the supportive strength needed for the capital's defense. There were 60 forts and 93 batteries protecting the city at the end of 1863.
At the end of the war in 1865, there were 68 forts surrounding the District of Columbia, connected with a system of batteries, rifle pits, batteries, blockhouses, and military roads. On June 23, 1865 orders were issued from the Department of Washington Headquarters to dismantle all but 17 forts, redoubts, and batteries that constituted the Defenses of Washington. All the forts were dismantled and the land was returned to the prior owners.
General Barnard described the Defenses of Washington as a:
"connected system of fortifications by which every prominent point, at intervals of 800 to 1,000 yards, was occupied by an enclosed field-fort, every important approach or depression of ground, unseen from the forts, swept by a battery for field-guns, and the whole connected by rifle-trenches which were in fact lines of infantry parapet, furnishing emplacement for two ranks of men and affording covered communication along the line, while roads were opened wherever necessary, so that troops and artillery could be moved rapidly from one point of the immense periphery to another, or under cover, from point to point along the line."