The American Civil War veteran’s pension fund made its last payment in 2001, 140 years after it made it was first set up in 1862. (The payment was to a widow who had married a very old veteran in the 1920s when he was very old and she was very young. Such marriages were widespread and we might speculate on what was in it for both parties.)
This may not actually have been the final payments, for the federal government was still paying a pension to the child of a veteran in January 2013.
All this despite the fact that the final Civil War veteran died in 1956.