Lake on the north central plateau of Amhara, Ethiopia, 1,800 m/5,900 ft above sea level; area 3,600 sq km/1,390 sq mi. It is about 75 km/47 mi long and 70 km/43 mi wide. The Blue Nile, the source of which lies just above Lake Tana, leaves the lake via the Tisisat Falls, where it is harnessed for hydroelectric power.
The disc represents the full moon, traditionally the most auspicious time for work and celebration. The disc is set towards the hoist. Effective date: 1 January 1981.