when it was assigned to the Army of Virginia under Maj. Gen. John Pope. At the Battle of Cedar Mountain, Crawford's brigade launched a surprise attack upon the Confederate left, routing a division that included the Stonewall Brigade. The Confederates counterattacked, however, and Crawford's brigade, which was unsupported by other units, was driven back with 50% casualties. At the Battle of Antietam, Crawford temporarily commanded his division when Brig. Gen. Alpheus S. Williams was elevated to command the XII Corps. Crawford's temporary command was short, however, when he was wounded in the right thigh. He stayed on the field until he became weak from loss of blood and had to be carried off. The wound took eight months to heal properly and he was unable to return to the field until May 1863, when he was given command of the Pennsylvania Reserves Division in the defenses of Washington, D.C. In commanding this division, Crawford was following in the footsteps of two Union Army luminaries: John F. Reynolds and George G. Meade. In June 1863, the Pennsylvania Reserves Division was added to the Army of the Potomac for the Gettysburg Campaign. Crawford was in a difficult situation. His training was as a surgeon, not as an infantry officer, and although he had experience at the brigade level, his eight-month recuperation meant that his skills were at minimal levels at the start of a critical campaign. Furthermore, the troops of his division had just spent six months on easy garrison duty around Washington and were not fully combat ready. On July 2, 1863, Crawford and his division arrived at Gettysburg in the rear of the V Corps, led by Maj. Gen. George Sykes. He was ordered to the front to assist the brigade of Col. Strong Vincent on Little Round Top, but the battle had already petered out by the time his division arrived. Meanwhile, the Confederate troops of Lt. Gen. James Longstreet's Corps had swept through the Devil's Den, driving the Union defenders back to Plum Run, a stream just to the west of Little Round Top, and an area that became known to the soldiers as "the Valley of Death". Crawford's division swept down the slope of Little Round Top along with the brigades of Colonels William McCandless and David J. Nevin. McCandless's brigade led the charge, but Crawford apparently desired some of the glory and seized his own division's