The Ox Mountains () are located west of the town. The town itself is named after the falls on the Owenmore River. Ballysadare is in the barony of Leyny formerly the túath of Luighne Connacht, and the barony of Tirerril, formerly the túath of Tír Olloíl. The Owenmore river forms the border between the baronies. Ballysadare also borders two other baronies in Co. Sligo, Carbury to the North and Tireragh to the West. Ballysadare is in the diocese of Achonry.