Kogin Jamma

Kogin Jamma (Amharic:Jamma)kogi ne wanda yake a tsakiyar kasar Habasha kuma rafi ne zuwa ga Abay (ko Blue Nile ).Yana yashe sassan yankin Semien Shewa na yankunan Amhara da Oromia.Babban Jamma yana gudana ta cikin tudu,manyan koguna masu zurfi da aka yanke da farko ta dutsen dutsen mai aman wuta sannan ta cikin yashi na Cretaceous da dutsen yashi, tare da dutsen Jurassic a ƙasa.Tana da magudanar ruwa mai girman murabba'in kilomita 15,782."Tana & Beles Integrated Water Resources Development: Project Appraisal Document (PAD), Vol.1", World Bank, 2 May 2008 (accessed 5 May 2009)Triburates sun haɗa da Wanchet.

Farkon ambaton wannan kogin yana cikin Gadla na Tekle Haymanot,wanda aka rubuta a ƙarni na sha huɗu.G.W.B. Huntingford, The historical geography of Ethiopia from the first century AD to 1704, (Oxford University Press: 1989), p. 69Ɗaya daga cikin abubuwan da aka ambata na farko na Turai shine ta mishan Pedro Páez,wanda shine Bature na farko da ya gani kuma ya kwatanta asalin Abay.A cewar Johann Ludwig Krapf,a cikin shekarun 1840s Jamma ta ayyana iyaka tsakanin Marra Biete da Moret,gundumomi biyu na tsohuwar lardin ko Sultanate na Shewa.Journals of the Rev. Messrs. Isenberg and Krapf, Missionaries of the Church Missionary Society, Detailing their proceedings in the kingdom of Shoa, and journeys in other parts of Abyssinia, in the years 1839, 1840, 1841 and 1842, (London, 1843), p. 290

 Manazarta