(William) Milo Mason was born on 24 May 1787 in Castleton, Vermont. He attended West Point, where he was a classmate of future superintendent Sylvanus Thayer. A career military man, Mason spent nearly thirty years as an artillery officer and quartermaster, rising to the rank of brevet major. He married Marie (or Maria) Lewis in 1815. Milo Mason died on 4 February 1837 in Washington, D.C.