It drains parts of the Semien Shewa Zones of the Amhara and Oromia Regions.

The Upper Jamma flows through steep, deep canyons cut first through volcanic rock and then through the Cretaceous sandstone and shaly sandstone, with Jurassic limestone at the bottom.

The earliest mention of this river is in the Gadla of Tekle Haymanot, which was written in the fourteenth century.

[1] According to Johann Ludwig Krapf, in the 1840s the Jamma defined the boundary between Marra Biete and Moret, two districts of the former province or Sultanate of Shewa.

This article related to a river in Ethiopia is a stub.