Semien Omo was bordered on the south by Debub Omo, on the west by Keficho Shekicho, on the northwest by the Oromia Region, on the north by Kembata Tembaro, on the northeast by part of the Oromia Region, on the east by the Bilate River which separated it from Sidama and another part of the Oromia Region, and on the southeast by the Amaro and Dirashe special woredas. The highest point in Semien Omo was Mount Guge (3568 m), west of Chencha. The administrative center of Semien Omo was Arba Minch; other towns included Areka, Boditi, Sawla and Sodo.