How many people died at the infamous Andersonville Prison? September 24, 2011 by Pamela Landy · Filed Under: American History More than 13,000 Union prisoners died at Andersonville, the largest Confederate military prison. Most died of neglect. The prison’s commandant, Captain Henry Wirz, was the only Civil War soldier executed for war crimes. Related PostsHow many people died on the Titanic when it sank?What was the name of director Jonathan Demme’s women-in-prison movie?For what crime did Malcolm X go to prison?When and where was the first U.S. federal prison established?How much prison time did Oliver North serve?