The Battle of Fort Stevens was fought in July 1864 between Jubal Early's Confederate Army of the Valley and Union Army forces defending Washington DC.
In June 1864, Robert E. Lee dispatched Early's II Corps, Army of Northern Virginia from Richmond to clear the Shenandoah Valley of Union forces and invade Maryland, thus threatening Washington DC and likely forcing Ulysses S. Grant to divert troops from the Siege of Petersburg to defend the capital. The II Corps drove off the Union Army of West Virginia at the 18 June Battle of Lynchburg before entering Maryland on 5 July near Sharpsburg, after which the rebels moved through Frederick on 7 July. Lew Wallace led a force of Union garrison troops to resist the rebel advance at the Battle of Monocacy, delaying Early's 40-mile advance of Washington. Early reached Silver Spring on 11 July, but he decided to rest his troops for a day before assaulting the capital's northern defenses. Grant sent the rest of the VI Corps and XIX Corps under Horatio Wright to Washington, and they began to disembark in Southeast Washington at noon on 11 July as Early's forces began to arrive at Fort Stevens.
The US Congress and prominent Washington residents fled both the 90° heat in the capital and the approaching Confederate army, although Lincoln remained in Northwest Washington. 31,000 Union troops and 1,000 artillery pieces manned 160 fortifications, batteries, and trenches, while, north of the Potoamc River, 484 heavy guns and 13,986 men faced off against Early. Early continued to delay his attack on Fort Stevens as he awaited the arrival of the rest of his heat-stricken army, enabling the Union to further fortify their defenses. At 3 PM, the Confederates initiated skirmishing, and, at 5 PM, Confederate cavalry pushed through the advance Union picket line before being driven back in a counterattack. Fort Stevens' artillery shelled Confederate positions and destroyed the houses that rebel sharpshooters used for protection. That same day, Lincoln, his wife Mary Todd Lincoln, and some officers visited the fort to observe the attack, and a surgeon next to Lincoln was wounded bya sharpshooter. Lincoln was ordered to take cover by Wright, and, overnight, additional Union reinforcements arrived. On 12 July, Early decided that Fort Stevens' defenses were too strong, and he withdrew that evening. Early retreated to Leesburg on 13 July, taking pride in scaring Lincoln despite his failure to take Washington.