Battle of Harpers Ferry - Background

Background

Harpers Ferry (originally Harper's Ferry) is a small town at the confluence of the Potomac River and the Shenandoah River, the site of a historic Federal arsenal (founded by President George Washington in 1799) and a bridge for the critical Baltimore and Ohio Railroad across the Potomac. It was earlier the site of the abolitionist John Brown's attack on the Federal arsenal there in 1859.

The town was virtually indefensible, dominated on all sides by higher ground. To the west, the ground rose gradually for about a mile and a half to Bolivar Heights, a plateau 668 feet (204 m) high, that stretches from the Potomac to the Shenandoah. To the south, across the Shenandoah, Loudoun Heights overlooks from 1,180 feet (360 m). And to the northeast, across the Potomac, the southernmost extremity of Elk Ridge forms the 1,476-foot-high crest of Maryland Heights. A Federal soldier wrote that if these three heights could not be held, Harpers Ferry would be "no more defensible than a well bottom."

As Gen. Robert E. Lee's Army of Northern Virginia advanced into Maryland, Lee expected that the Union garrisons that potentially blocked his supply line in the Shenandoah Valley, at Winchester, Martinsburg, and Harpers Ferry, would be cut off and abandoned without firing a shot (and, in fact, both Winchester and Martinsburg were evacuated). But the Harpers Ferry garrison had not retreated. Lee planned to capture the garrison and the arsenal, not only to seize its supplies of rifles and ammunition, but to secure his line of supply back to Virginia.

Although he was being pursued at a leisurely pace by Maj. Gen. George B. McClellan and the Union Army of the Potomac, outnumbering him more than two to one, Lee chose the risky strategy of dividing his army to seize the prize of Harpers Ferry. While the corps of Maj. Gen. James Longstreet drove north in the direction of Hagerstown, Lee sent columns of troops to converge and attack Harpers Ferry from three directions. The largest column, 11,500 men under Jackson, was to recross the Potomac and circle around to the west of Harpers Ferry and attack it from Bolivar Heights, while the other two columns, under Maj. Gen. Lafayette McLaws (8,000 men) and Brig. Gen. John G. Walker (3,400), were to capture Maryland Heights and Loudoun Heights, commanding the town from the east and south.

McClellan had wanted to add the Harpers Ferry garrison to his field army, but general-in-chief Henry W. Halleck had refused, saying that the movement would be too difficult and that the garrison had to defend itself "until the latest moment," or until McClellan could relieve it. Halleck had probably expected its commander, Col. Dixon S. Miles, to show some military knowledge and courage. Miles was a 38-year veteran of the U.S. Army and the Mexican-American War, but who had been disgraced after the First Battle of Bull Run when a court of inquiry held that he had been drunk during the battle. Miles swore off liquor and was sent to the supposedly quiet post at Harpers Ferry. His garrison comprised 14,000 men, many inexperienced, including 2,500 who had been forced out of Martinsburg by the approach of Jackson's men on September 11.

On the night of September 11, McLaws arrived at Brownsville, 6 miles northeast of Harpers Ferry. He left 3,000 men near Brownsville Gap to protect his rear and moved 3,000 others toward the Potomac River to seal off any eastern escape route from Harpers Ferry. He dispatched the veteran brigades of Brig. Gens. Joseph B. Kershaw and William Barksdale to seize Maryland Heights on September 12. The other Confederate columns were making slow progress and were behind schedule. Jackson's men were delayed at Martinsburg. Walker's men were ordered to destroy the aqueduct carrying the Chesapeake and Ohio Canal across the Monocacy River where it empties into the Potomac, but his engineers had difficulty demolishing the stone structure and the attempt was eventually abandoned.

Walker reentered Virginia, in Loudoun County on the 9th, across from Point of Rocks. Walker was escorted by Col. E.V. White, Loudoun native, and his 35th Battalion of Virginia Cavalry. White was unhappy with the assignment and preferred to be with the rest of the army. Unfortunately White had gotten into an altercation with Maj. Gen. J.E.B. Stuart in Frederick and was subsequently ordered back to Virginia by Lee. Whether or not his disposition was to blame, White led Walker on a meandering route around the Short Hill Mountain to reach the base of Loudoun Heights four days later on September 13. So the attack on Harpers Ferry that had been planned for September 11 was delayed, increasing the risk that McClellan might engage and destroy a portion of Lee's army while it was divided.