Fort Duncan

In June 1864, Confederate Gen. Robert E. Lee sent Gen. Jubal A. Early's corps from the Richmond battlefields to the Shenandoah Valley to counter Union Gen. David Hunter's army. After driving Hunter into West Virginia, Early invaded Maryland to attack Washington, D.C., draw Union troops from Richmond, and release Confederate prisoners held at Point Lookout. On July 9, Early ordered Gen. Bradley T. Johnson's cavalry brigade eastward to free the prisoners, and the next day Johnson sent Maj. Henry Gilmer's regiment to raid the Baltimore area. Union Gen. Lew Wallace delayed Early at the Battle of Monocacy on July 9, and Federal reinforcements soon strengthened the capital's defenses. Early attacked near Fort Stevens on July 11-12 and then withdrew to the Shenandoah Valley with the Federals in pursuit, stopping them at Cool Spring on July 17-18. Although he failed to take Washington or free the prisoners, he succeeded in diverting Federal resources. When Early approached the defenses of Harpers Ferry with his main force on July 4, 1864, the Federals answered his approach with fireworks and then with real artillery shells from Fort Duncan on Maryland Heights and the other fortifications there. For four days, Union forces delayed Early's advance, enabling reinforcements to reach the defensive lines around Washington, the principal Confederate objective. Harpers Ferry threatened the success of any Confederate invasion of the North. In September 1862, during the Antietam Campaign, Gen. Thomas J. "Stonewall" Jackson captured the place easily to protect Lee's rear because the defenses were so rudimentary that he occupied the high ground and threatened to shell the town to pieces, producing the largest surrender of Union troops in the war. Soon after the Confederates retreated to Virginia, the Federals constructed works on the heights, including Fort Duncan, that were unlikely to be overcome. Engineers chose the site for Fort Duncan because of its elevation and the right-angle bend in the Potomac River that protected its flanks. When Lee invaded again in 1863, he bypassed Harpers Ferry altogether, and in 1864 Early found the works too strong to capture, moved around them, and relied on the speed of his march to stay ahead of any threat to his rear.

Maryland · United States