The dark shape under the trees is what’s left of the north wall of Fort Evans, an earthwork fortified with a few cannon in open-top embrasures. You’re looking south from Edwards Ferry Road on the east side of Leesburg.

The remains of the low-walled fort, built in August and September 1861, is on private property. Independent historian Craig Swain, who lives nearby and took the photo and, with permission of the land owner, paced off the dimensions for a sketch, says the earthwork was:

“Placed on a knoll about 400 feet above sea level just east of town, [it] lay next to Edwards Ferry Road about half a mile north of the [Alexandria-Leesburg Pike (Modern Virginia Highway 7)].  The ground in front of the fort was at the time a mix of broken ground descending to Goose Creek, about a mile and a half east, which flowed into the Potomac near Edwards Ferry.”

Men of the 13th occupied the fort and its vicinity at various times that fall and winter, along with the three other infantry regiments of Col. (later Gen.) Shanks Evans’s Seventh Brigade, the 1st battery of the Richmond Howitzers and four companies of the 4th and 6th Virginia cavalry. Evans used the fort as his headquarters.

On the night of Oct. 20, 1861, before the Battle of Leesburg/Ball’s Bluff began the next morning, the fort reportedly mounted some Quaker cannon—cut cedar logs with their ends painted black. Torches were burning inside the walls, says independent historian Eugene Scheel, which misled Union scouts from a Minnesota regiment into thinking Fort Evans was stronger than it was.

Irony: In the 1950s, Lester Carr, a great grandson of one of those scouts, Pelig Carr, bought the land the fort sits on and built his house next to it.

Via To The Sound of The Guns.