See the caption under the picture.

I took these pictures on a previous visit to Indian Mound Cemetery, which was also the site of Fort Pearsall.

“Fort Pearsall was on or in view of this site.”
Job Pearsall built a fort as protection against the Indians in 1754 on Lot 16, granted by Fairfax in 1749 containing 323 acres, including part of Indian Mound Cemetery.
On May 14, 1756, Gen. Washington assigned 45 men and 5 officers and later 94 soldiers to defend Pearsall’s fort during the French and Indian War.