Ghana, officially the Republic of Ghana, is a country located along the Gulf of Guinea and Atlantic Ocean, in the subregion of West Africa. Spanning a land mass of 238,535 km2 (92,099 sq mi), Ghana is bordered by the Ivory Coast in the west, Burkina Faso in the north, Togo in the east, and the Gulf of Guinea and Atlantic Ocean in the south. Ghana's borders follow the lines of what were four separate British colonial territories: Gold Coast, Ashanti, the Northern Territories and British Togoland. Those were unified as an independent dominion within the British Commonwealth on 6 March 1957. Ghana's population of approximately 30 million spans a variety of ethnic, linguistic and religious groups. According to the 2010 census, 71.2% of the population was Christian, 17.6% was Muslim, and 5.2% practised traditional faiths. Its diverse geography and ecology ranges from coastal savannahs to tropical rain forests. Ghana is a unitary constitutional democracy led by a president who is both head of state and head of the government. Ghana's growing economic prosperity and democratic political system have made it a regional power in West Africa.