Unac is a commune in the Ariège department in southwestern France.
Unac River is a river of Bosnia and Herzegovina. It rises beneath Šator mountain, flows through the municipality of Drvar and finally meets Una River in Martin Brod. Also runs through two deep and rugged krastic canyons and it is dammed to form small Prekajsko Lake and larger Župica Lake, before it reach town of Drvar.
Lower course of the Unac River and its canyon is included into the Una National Park.