Sokoto is a city located in the extreme northwest of Nigeria, near to the confluence of the Sokoto River and the Rima River. As of 2006 it has a population of 427,760. Sokoto is the modern day capital of Sokoto State (and its predecessor, the Northwestern State).The name Sokoto (which is the modern/anglicised version of the local name, Sakkwato) is of Arabic origin, representing suk, 'market'. It is also known as Sakkwato, Birnin Shaihu da Bello or "Sokoto, Capital of Shaihu and Bello").Being the seat of the Sokoto Caliphate, the city is predominantly Muslim and an important seat of Islamic learning in Nigeria. The Sultan who heads the caliphate is effectively the spiritual leader of Nigerian Muslims.