The Gambia, officially the Republic of The Gambia, is a country in West Africa. It is the smallest country within mainland Africa and is surrounded by Senegal, except for its western coast on the Atlantic Ocean. The Gambia is situated on both sides of the lower reaches of the Gambia River, the nation's namesake, which flows through the centre of the Gambia and empties into the Atlantic Ocean. It has an area of 10,689 square kilometres (4,127 sq mi) with a population of 1,857,181 as of the April 2013 census. Banjul is the Gambian capital and the country's largest metropolitan area. The largest cities are Serekunda and Brikama.