The Ras Mkumbuu Ruins are located on the west coast of the Tanzanian island of Pemba, part of the Zanzibar Archipelago. They lie close to the village of at the end of a long narrow peninsula known as Ras Mkumbuu, which lies to the northwest of the town of Chake-Chake. The ruins mainly date from the thirteenth and fourteenth centuries, though there are indications that they were built over older foundations. Notable among these ruins are those of a large mosque which was for some time the largest structure of its type in sub-Saharan Africa.