Abeokuta is the largest city and capital of Ogun State in southwest Nigeria. Abeokuta and the surrounding area had a population of 593,140. Abẹokuta lies in fertile country, the surface of which is broken by masses of grey granite. It is spread over an extensive area, being surrounded by mud walls 18 miles in extent. Palm-oil, timber, rubber, yams and shea-butter are the chief articles of trade. It lies below the Olumo Rock, home to several caves and shrines. The town depends on the Oyan River Dam for its water supply, which is not always dependable.