Credit: Library of Congress Prints and Photographs Division
After three days of bloodletting, Lee's Army began its retreat from Gettysburg on July 4, 1863. Lee's wagon train of wounded was said to be more than seventeen miles long. At Hagerstown, Maryland, Lee found the Potomac too high to cross. Setting his exhausted men to work digging earthworks, he awaited the inevitable attack. As Meade waited for reinforcements, engineers erected a pontoon bridge across the river that enabled Lee's army to cross back to safety.
