It is a unitary presidential republic and is the westernmost country in the mainland of the Old World, or Afro-Eurasia. It owes its name to the Senegal River, which borders it to the east and north. Senegal covers a land area of almost  and has a population of around  million. The state was formed as part of the independence of French West Africa from French colonial rule. Because of this history, the official language is French. Like other post-colonial African states, the country includes a wide mix of ethnic and linguistic communities, with the largest being the Wolof, Fula, and Serer people, and the Wolof and French languages acting as lingua francas.