Susannah Buckles Flanagan said her father died of natural causes, The Washington Post reported.
"I knew there'd be only one someday," Buckles said not too many years ago. "I didn't think it would be me."
Buckles was a 16-year-old Missouri farm boy when he ditched school, talked his way into the Army and was shipped to France in 1918 where as a rear-echelon ambulance driver in 1918 he "saw the results" of war's savagery.
The Post said researchers say only a 109-year-old Australian man and a 110-year-old British woman are still alive from the approximately 65 million people mobilized for the war that was to end all wars.
After the war, Buckles traveled the world working on commercial ships. He spent more than three years as a civilian prisoner in the Pacific theater during World War II. Eventually, he and his wife bought a cattle farm near Charles Town, W.Va., where he spent the remainder of his life.
Buckles will be buried at Arlington National Cemetery.