William Mason (10 September 1786-13 January 1860) was a member of the US House of Representatives (D-NY 21) from 4 March 1835 to 3 March 1837, succeeding Henry Mitchell and preceding John C. Clark. Born in Lebanon, Connecticut, he practiced medicine in Preston, New York before serving as county clerk from 1820 to 1821, in the state assembly from 1821 to 1822, and in Congress.