American Civil War: The first Northern prisoners arrive at the Confederate prison at Andersonville, Georgia.

The American Civil War was a civil war in the United States between the Union and the Confederacy, which was formed in 1861 by states that had seceded from the Union. The central conflict leading to war was a dispute over whether slavery should be permitted to expand into the western territories, leading to more slave states, or be prohibited from doing so, which many believed would place slavery on a course of ultimate extinction.

The Union was the central government of the United States during the American Civil War. Its civilian and military forces resisted the Confederacy's attempt to secede following the election of Abraham Lincoln as president of the United States. Lincoln's administration asserted the permanency of the federal government and the continuity of the United States Constitution.

The Confederate States of America (CSA), also known as the Confederate States (C.S.), the Confederacy, or the South, was an unrecognized breakaway republic in the Southern United States from 1861 to 1865. It comprised eleven U.S. states that declared secession: South Carolina, Mississippi, Florida, Alabama, Georgia, Louisiana, Texas, Virginia, Arkansas, Tennessee, and North Carolina. These states fought against the United States during the American Civil War.

The Andersonville National Historic Site, located near Andersonville, Georgia, preserves the former Andersonville Prison, a Confederate prisoner-of-war camp during the final fourteen months of the American Civil War. Most of the site lies in southwestern Macon County, adjacent to the east side of the town of Andersonville. The site also contains the Andersonville National Cemetery and the National Prisoner of War Museum. The prison was created in February 1864 and served until April 1865.