In the summer of 1865, Secretary of War Edwin Stanton asked Barton to accompany an expedition to construct a cemetery on the site of Camp Sumter, better known today as Andersonville Prison, in Georgia. The expedition was led by Assistant Quartermaster General Captain James Moore, a veteran of the Army’s cemetery system who supervised over 50,000 burials during and after the war. During the journey from Washington, D.C., a contentious relationship developed between Barton and Captain Moore, leading the latter to remark, “God dammit to hell, some people don’t deserve to go anywhere, and what in the hell does she want to go for?”

While at Andersonville, Barton and her staff worked with former Andersonville POW Dorence Atwater to locate the families of prisoners who perished using a “death list” that Atwater kept during his detainment. The team worked with members of the 137th United States Colored Troops to mark graves with wooden headboards listing soldiers’ names, rank, unit and death date. Using Atwater’s death list and the available burial information, Barton began to produce an exact record of the Andersonville dead. Captain Moore’s disdain was so great that he restricted Barton and her team to working by candlelight after dark. Following weeks of hard work, Andersonville National Cemetery was dedicated on August 17, 1865 with Barton on hand to raise the American flag.