The Republic of the Sudan is a country in Northeast Africa. It borders the Central African Republic to the southwest, Chad to the west, Egypt to the north, Eritrea to the northeast, Ethiopia to the southeast, Libya to the northwest, South Sudan to the south, and the Red Sea. It has a population of 45.7 million people as of 2022 and occupies 1,886,068 square kilometres (728,215 square miles), making it Africa's third-largest country by area and the third-largest by area in the Arab League. It was the largest country by area in Africa and the Arab League until the secession of South Sudan in 2011; since then both titles have been held by Algeria. Its capital city is Khartoum, and its most populous city is Omdurman (part of the metropolitan area of Khartoum).