Located at an elevation of about 4,010 metres (13,160 ft), its surface area presently fluctuates between 1.7–2.7 square kilometres (0.66–1.04 sq mi) but in the past it was considerably larger; this led to humans going to the lake and creating archeological sites there.

The lake lies at an elevation of 4,010 metres (13,160 ft)[2] in the Antofagasta Region, northern Chile.

Wetlands occur on the eastern shores,[6] and the local flora and fauna depend on the water supply to the lake.

[11] At that time between 13,800 – 9,100 calibrated radiocarbon years ago[12] or 12,800 – 10,300 years ago Tuyajto Lake was much larger, having an area of 14.6 square kilometres (5.6 sq mi)[13][14]-18 square kilometres (7 sq mi)[15] and its uppermost shoreline reached 4,080 metres (13,390 ft) elevation.

[7] The regional geology is characterized by a number of stratovolcanoes with ages ranging from Miocene to Holocene and ignimbrites of Miocene to Holocene age that form a thick layer underneath the volcanoes;[24] the Tuyajto Ignimbrite which crops out on the western and northern shores of the lake has been dated to 500,000 ± 500,000 years ago.

[1] Moisture originates from the Atlantic Ocean, the equatorial Pacific and the Gran Chaco in Argentina;[27] it falls mostly during winter unlike the rest of the Altiplano where summer precipitation dominates.

[3] Precipitation is variable both over annual and millennial timescales, with complex regional variations during El Nino and La Nina years and with past increases during the Central Andean Pluvial Events between 18,000 – 14,100 and 13,600 – 10,600 years ago, during which Lake Tuyajto rose.

[31] Such archeological sites close to then-shorelines are common for the "Tambillo stage" of early human population in the Atacama.