Khartoum is located in the middle of the populated areas in Sudan, at almost the northeast center of the country between 15 and 16 degrees latitude north, and between 31 and 32 degrees longitude east. Khartoum marks the convergence of the White Nile and the Blue Nile, where they join to form the bottom of the leaning-S shape of the main Nile (''see map, upper right'') as it zigzags through northern Sudan into Egypt at Lake Nasser.