Blueprint for Glory: Organizational Changes in the Army of the Potomac Prior to the Battle of Gettysburg

Th e Army of the Potomac under the command of Maj. Gen. Joseph Hooker faced a very real crisis in May 1863. Already reeling from its recent defeat at Chancellorsville, the army was about to lose fi ft yfi ve veteran infantry regiments in May and June due to the expiration of their terms of service. When combined with the more than 17,000 casualties sustained at Chancellorsville, the army would embark upon the next campaign reduced by some 40,000 men.1 Clearly, major organizational reforms that would aff ect all three of the army’s combat arms— infantry, cavalry, and artillery— would be needed in the face of such losses. To be sure, the Army of the Potomac was a hardened and veteran force, although one beset by organizational and leadership problems and a record of failure. Chief among the army’s problems were high rates of unit loss and replacement, frequent leadership turnover at midand upperechelons, and an organizational structure that had been rendered largely obsolescent by evolving battlefi eld conditions. Major organizational changes were in the offi ng. As the army approached the fi eld at Gettysburg, its basic structure would appear largely unaltered from its Chancellorsville confi guration; the army in both campaigns comprised seven infantry corps with their supporting artillery, an artillery reserve, and a cavalry corps. However, this macro picture obscures the myriad disruptive organizational changes that had altered the composition of nearly every unit in all three branches of service. Th ese changes, combined with the mustering out of so