[5][6] Clarens was constructed between 1814 and 1816 in what was then Fairfax County, Virginia, three miles (5 km) to the west of Alexandria.

Reverend George Smith operated his prominent "Fairfax School" at Clarens.

[7] During the American Civil War, Clarens was used as a hospital for Union Army soldiers.

[5] After the war, James Murray Mason selected Clarens as the estate at which he planned to retire.

[6] Confederate Army General Robert E. Lee also visited Mason at Clarens after the war.