 He was ordered by General-in-chief Henry W. Halleck to hold the important U.S. arsenal and railroad bridges until he was relieved by Union forces under Maj. Gen. George B. McClellan.Lee sent columns converging from three directions to surround Harpers Ferry.Unfortunately for him and his army, Miles apparently treated his orders to defend the town too literally and stationed most of his 14,000 men just outside the town to the west, on Bolivar Heights, neglecting the commanding heights to the northeast (Maryland Heights) and to the south (Loudoun Heights).