Maryland campaign

(Wikipedia) ... On September 3, just two days after the Battle of Chantilly, Lee wrote to President Davis that he had decided to cross into Maryland unless the president objected. On the same day, Lee began shifting his army north and west from Chantilly towards Leesburg, Virginia. On September 4, advance elements of the Army of Northern Virginia crossed into Maryland from Loudoun County. The main body of the army advanced into Frederick, Maryland, on September 7. The 55,000-man army had been reinforced by troops who had been defending Richmond—the divisions of Maj. Gens. D.H. Hill and Lafayette McLaws and two brigades under Brig. Gen. John G. Walker—but they merely made up for the 9,000 men lost at Bull Run and Chantilly. Continued