Fort Woodbury was part of the Arlington Line, an extensive network of fortifications erected in present-day Arlington County, Virginia to protect Washington, D.C. from Confederate attack during the American Civil War.

Construction began on the Arlington Line in May 1861, shortly after war broke out, and accelerated after the Union's defeat at the First Battle of Bull Run in July 1861.

Fort Woodbury was a lunette with a 275-yard perimeter and 19 emplacements for 13 guns.

The marker's inscription reads: "Immediately behind the present Court House stood Fort Woodbury, a Iunette in the Arlington Line constructed in August 1861.

Woodbury, the Engineer who designed and constructed the Arlington Line."