On June 9, 1863, President Abraham Lincoln, responding to Robert E. Lee's impending invasion of Maryland and Pennsylvania, called for 100,000 volunteers from Pennsylvania, New York, and Ohio to help repel the invasion, with only about 33,000 recruits answering his call. Secretary of War Edwin M. Stanton ordered the creation of two military departments, the Departments of the Susequehanna and Monongahela, to organize these militia and defend the state of Pennsylvania. The Department of the Susquehanna consisted of all troops east of Johnstown and the Laurel Highlands, and it was initially headquartered at Chambersburg. It was placed under the command of Major General Darius N. Couch, who had formerly commanded II Corps, Army of the Potomac.