Over 30,000 soldiers of both armies lay wounded in temporary field hospitals at the close of the Battle of Gettysburg. As the Medical Director of the Army of the Potomac, Dr. Letterman and his staff before the battle ended ordered more medical supplies to be brought to Gettysburg and he sent his ambulance corps over the field to move the wounded into a more central medical stations.
A central hospital was established on the York Pike east of Gettysburg and near the railroad and named Camp Letterman after Dr. Letterman. Wounded soldiers were taken from the field hospitals by horse-drawn ambulances to the new camp where they were housed in large canvas tents. Unlike the rigors of a field hospital, the new camp had cots with clean sheets and pillows.
By August 7, 1863 all of the corps and field hospitals were closed and Camp Letterman was the only hospital remaining with over 3,000 patients. The camp remained at Gettysburg until November 1863 when the last remaining patients left, the tents were packed, and the doctors and nurses left for other battlefield hospitals.