Kenya (/; locally (listen)), officially the Republic of Kenya (Swahili: Jamhuri ya Kenya), is a country in Africa with its capital and largest city in Nairobi. Kenya's territory lies on the equator and overlies the East African Rift, covering a diverse and expansive terrain that extends roughly from Lake Victoria to Lake Turkana (formerly called Lake Rudolf) and further south-east to the Indian Ocean. It is bordered by Tanzania to the south and south-west, Uganda to the west, South Sudan to the north-west, Ethiopia to the north and Somalia to the north-east. Kenya covers 581,309 km (224,445 sq mi) has a population of approximately 48 million. Kenya's capital and largest city is Nairobi, while its oldest city and first capital is the coastal city of Mombasa. Kisumu City is the third largest city and a critical inland port at Lake Victoria. Other important urban centres include Nakuru and Eldoret.