 Isham, who did not marry and lived at 471 Park Avenue in Manhattan, was a member of the Maidstone Club (in East Hampton, New York), Ardsley Club (in Irvington, New York), the Metropolitan Club, the Players' Club, and the University Club of New York.On June 12, 1914, Isham suffered from an aneurysm of the arteries and died on the Maidstone Club golf course in East Hampton.He was buried in Woodlawn Cemetery in the Bronx.