Lake Tana (also spelled T'ana, sometimes called "Dembiya" after the region to the north of the lake) is the source of the Blue Nile and is the largest lake in Ethiopia. Located in Amhara Region in the north-western Ethiopian highlands, the lake is approximately 84 kilometers long and 66 kilometers wide, with a maximum depth of 15 meters, and an elevation of 1,840 meters. Lake Tana is fed by the Lesser Abay, Reb and Gumara Rivers and its surface area ranges from 3,000 to 3,500 km² depending on season and rainfall. The lake Tana level has been regulated since the construction of the control weir where the lake discharges into the Blue Nile, which regulates the flow to the Tis Abbai falls and hydro-power station.
The lake has a number of islands. Seven to eight of the lake Tana Island had monasteries on them.
The monasteries are believed to rest on earlier religious sites and include the fourteenth century Debre Maryam, the eighteenth century Narga Selassie, Tana Qirqos (said to have housed the Ark of the Covenant before it was moved to Axum), and Ura Kidane Mehret, known for its regalia. A ferry service links Bahir Dar with Gorgora via Dek Island and various lake shore villages.


Lake Tana supports a notable fishing industry; according to the Ethiopian Department of Fisheries and Aquaculture, 1,454 tonnes of fish are landed each year at Bahir Dar, which the department estimates is 15% of its sustainable amount. Lake Tana, picture, pictures, photo, photos.