On 17 June 1863, early in the Gettysburg Campaign, the Union XII Corps camped just north of here. The men left Fairfax Court House at daybreak, ate breakfast at Hunter's Mill, and halted by 11 AM because of extreme heat, 99 degrees in the shade. Devastated by sunstroke casualties two days earlier during the grueling 25-mile-long march north, the Corps continued to suffer. Brig. Gen. Alpheus S. Williams, the First Division Commander, noted on the 17th that "the dry old grass of the fields and woods got on fire, and filled the air with smoke and additional heat."