Juba is the capital and largest city of South Sudan. The city is situated on the White Nile and also serves as the capital of the Central Equatori…Juba is the capital and largest city of South Sudan. The city is situated on the White Nile and also serves as the capital of the Central Equatoria State. It is the most recently declared national capital and had a population of 525,953 in 2017. It has an area of 52 km², with the metropolitan area covering 336 km².