On June 15, 1863, President Abraham Lincoln issues a proclamation in which he calls for the mustering of new militia in the Mid-Atlantic states of Maryland, West Virginia, Pennsylvania and Ohio—in part to help protect Washington, D.C., America’s capital city.
Throughout June, Confederate General Robert E. Lee’s Army of Northern Virginia was on the move. He had pulled his army from its position along the Rappahannock River around Fredericksburg, Virginia, and set it on the road to Pennsylvania. Lee and the Confederate leadership decided to try a second invasion of the North to take pressure off Virginia and to seize the initiative against the Army of the Potomac. The first invasion, in September 1862, failed when the Federals fought Lee’s army to a standstill at the Battle of Antietam in Maryland.