Fort Negley is the Large Civil War-era Union stone fort. After its capture in 1862, Nashville was developed by Union forces into the most fortified city in North America, second only to Washington, D.C. A series of forts ringed the city, the largest and southernmost being Fort Negley, named for U.S. Gen. James Scott Negley, provost marshal and commander of Federal forces in Nashville. Fort Negley was the largest fortification built by the occupying Union Army in Nashville and the largest inland stone fort built during the Civil War. Measuring 600 feet by 300 feet, Negley covered four acres and was constructed from October to December 1862. The stronghold was constructed by conscript laborers, both slaves and free blacks, of stone, logs, earth, and railroad iron. More than 2700 African American men worked to build Fort Negley; only 300 were paid for their labor.