Colquhoun is a surname of Scottish origin. It is a habitational name from the barony of Colquhoun in Dumbartonshire. The name is thought to be derived from the Gaelic elements còil ("nook"), cùil ("corner"), or coill(e) ("wood") + cumhann ("narrow").
Calhoun, Calhoon, Colhoon, Colhoun, Hoon, Cahoun, and Cahoon are variants of the surname Colquhoun. They are generally found only in the United States of America and Canada.