Dassu Tehsil is the district headquarters of Kohistan District, Khyber-Pakhtunkhwa, Pakistan. It had 15 Union Councils before the separation of the Kandia valley. Since its being named as Tehsil, the Dassu subdivision has 11 Union Councils. The total population of Dassu according to 1998 Census was 137,519, in 21,487 households.