The
Umba River is located in northeastern
Tanzania in
Tanga Region. It rises in Schageiuforest (Shagayu) in the West
Usambara Mountains at 2,000 m altitude and flows on the north side of the mountain range to the east. At Lelwa it empties the Mbalamu River, which comes from the extreme north of the Usambara Mountains, and the Mglumi River into the Umba. Just before the Umba flows into the
Indian Ocean, it cross the border to
Kenya. The mouth itself marks the most eastern point on the border between Tanzania and Kenya, which they largely made in a straight line to the northwest towards
Lake Victoria in the 19th Century. On the upper reaches of the river in the mid-1960s rich deposits of precious stones, including
sapphires and
Spessartine, were discovered. Also on the river is the Umba River Game Reserve, a wildlife reserve that includes along with the
Mkomazi Game Reserve, about 2,600 km².