Lake Eyasi, located south of the Serengeti National Park and immediately southwest of the Ngorongoro Crater in the Ngorongoro Highlands area of Tanzania is one of several lakes on the floor of the Great Rift Valley and it lies west of Lake Manyara and approximately 95 miles (155 km) southwest of Arusha. At an elevation of about 3,400 feet (1,040 m), the lake covers an area of about 400 square miles (1,050 square km) and occupies the bottom of a bowl like depression in a region of volcanic activity.
The walls of the lake are purple lava enclosing a broad expanse of white alkaline shallows with some fresh water at depths below 33 feet (10 m). The lake has no outlet; its main inlet is the Sibiti River on the southwest. The lake drains an area of about 25,300 square miles (65,500 square km). Greater and lesser flamingos inhabit the lake shore in vast flocks.