Mongalla or Mangalla is a Payam in Juba County, Central Equatoria State in South Sudan, on the east side of the Bahr al Jebel or White Nile river. It lies about 75 km by road northeast of Juba. The towns of Terekeka and Bor lie downstream, north of Mongalla. Mongalla is an important center for gauging the flow of the Nile, with measurements taken regularly from 1905 until 1983, and since 2004.