Which lake in Ethiopia is the source of the Blue Nile?

Lake Tana is the Ethiopian lake that supplies the Blue Nile.

Located in Ethiopia’s northwestern highlands, Lake Tana is the country’s largest lake. Several rivers feed it, including the Gilgel Abay, Gumara, Rib and Megech. Its outlet near Bahir Dar becomes the Blue Nile, called the Abay in Ethiopia, which then flows through deep gorges before crossing into Sudan.

The lake’s outflow passes over the Blue Nile Falls, or Tis Abay, before continuing toward Khartoum, where the Blue Nile joins the White Nile to form the Nile. Seasonal rains strongly affect Tana’s water level and the river’s flow.

A common mix-up is confusing the lake with Gish Abay, a spring and river source sometimes described as the Blue Nile’s ultimate source. Lake Tana is the major lake source named in the question. It is also known for medieval island monasteries and an unusually large number of endemic fish species.