The Situation on 5 September: Jackson's Command crosses the Potomac at White's Ford; the "Stonewall" Division, Taliaferro's Brigade in the lead. By evening MGen Jackson is at Buckeystown on the Frederick Road. Now Commander of Confederate forces north of the Potomac, he orders MGen DH Hill to consolidate his Brigades already in Maryland and join at Buckeystown; Hill does so by late evening.
In the afternoon, following Jackson, MGen Stuart takes most of his Cavalry Division across at White's Ford and deploys as screen south and east, pushing out to near Poolesville. A squadron of Federal Cavalry from the 1st Massachusetts skirmish with Stuart there, many of it's troopers captured.
MGen McClellan, commander of the Federal forces at Washington City, on word of the Confederate moves to Leesburg and into Maryland, sends BGen Pleasonton's cavalry to scout the enemy, and pushes elements of the Army to the perimeter of the Defenses of Washington: Sumner's and Banks' Corps to near Rockville; Couch's Division (IV Corps) to Offutt's Crossroads, and Burnside's Corps near Beltsville by day's end.
Anderson's (NC) Brigade
D. H. Hill's Division
Stuart's Cavalry Division