وادي درعة
The southern half of Guelmin-Es Semara formed part of the Western Sahara. The region was bordered to the north by Souss-Massa-Drâa and to the west by Laayoune-Boujdour-Sakia El Hamra, with the Algerian province of Tindouf to the east. Its disputed territory in the Western Sahara bordered the Mauritanian Tiris Zemmour Region. Guelmin-Es Semara had a coastline on the Atlantic Ocean, with the Spanish Canary Islands lying off it. The Draa River, at 1,100 km the longest in Morocco, flowed through the region into the Atlantic Ocean near Tan-Tan.