Located close to Barstow, this lake had the shape of a cloverleaf and covered four basins named Coyote, Cady/Manix, Troy and Afton.

The lake did not immediately include the Afton basin; its integration occurred only about 190,000 years ago, most likely due to a catastrophic flood.

Lake Manix lasted until 25,000–13,800 years ago, when Afton Canyon formed, either through slow downcutting or a large outburst flood.

[12] Yermo, together with Dunn and Newberry Springs, are present-day towns whose locations would have been close to the shore of, or submerged beneath, Lake Manix.

[31] This draining cut 120 metres (390 ft) deep into the sediments of Lake Manix, removing about 2.815 cubic kilometres (0.675 cu mi) of material and depositing it below Afton Canyon.

[32] The erosion has exposed sediments of Lake Manix, making their climatic records accessible to research.

[34] In many places, wind- and water-driven erosion has removed deposits from Lake Manix and obscured shorelines.

These lake fillings were influenced by shifts in storm tracks caused by the Laurentide ice sheet.

[46] Tufa, a type of calcium carbonate deposit that develops in waterbodies,[47] formed within Lake Manix.

While the lake may have been warm during oxygen isotope stage 12 and possibly nourished from early summer runoff,[50] after that point it was much colder, with water temperatures not rising above 4 °C (39 °F).

[59] Bird species whose skeletons have been found in sediments of Lake Manix include the western grebe and the white pelican.

[2] Other bird skeletons found there have been attributed to the species Aquila chrysaetos (Golden eagle),[60] Branta canadensis (Canada goose),[61] Ciconia maltha (an extinct stork),[62] Erismatura jamaicensis (Ruddy duck),[60] the genus Grus,[60] Nyroca valisineria,[61] Nannopterum auritum (double-crested cormorant), Phoenicopterus copei and Phoenicopterus minutus.

[63] Mammal genera at Lake Manix included Canis, Felis, Equus, Camelops, Tanupolama, Ovis, Bison, Mammuthus and Nothrotherium.

[67] Anodonta especially was probably very common in Lake Manix and other paleolakes, considering the large shell deposits left by it.

[65] Lake Manix during the time of its existence featured reedy marshes surrounded by juniper-sage vegetation and Pinyon-juniper woodlands in the mountains.

[72] The present natural vegetation consists mostly of the creosote bush; starting in 1964, parts of the lake bed were used for groundwater-supported center pivot irrigation-driven agriculture before increasing water-pumping costs after 1980 caused their abandonment.

[73] Present-day climates at the location of Lake Manix are dry and warm, with the mean temperature at Barstow 21.2 °C (70.2 °F).

[75] About 500,000 years ago, it reached the Cady Basin of Lake Manix, based on tephrochronological dating of the Bishop Tuff.

[5] The presence of deposits with chaotically bedded rocks suggests that the breakthrough took the form of a catastrophic flood[41] that may have been a mudflow.

[76] Afton Basin had a bottom at an altitude of c. 460 metres (1,510 ft) before; as it was integrated into Lake Manix, sedimentation progressively filled it.

[80] Finally, radiocarbon dating in 2015 yielded highstand ages of 43,000, 39,700, 36,100, 34,100, 31,600, 30,800, 29,400, 27,200 and 25,600 years ago, coinciding with cold and wet periods in speleothem records in Arizona and New Mexico.

[26] Alternative theories assume a much slower formation of the Afton Canyon outlet,[16] based on the presence of several terraces and possible recessional landforms.

[86][87] The formation of the path to Afton Canyon was probably aided by the Manix Fault, which had left easily eroded sediments.

[31] Such artifacts include bifaces, disks, flakes and hammerstones, which were grouped as the "Lake Manix Industry".

[93] Dates obtained on the desert varnish they were embedded in yielded ages of 400–32,000 years before present, indicating that these items have varying origins and cannot be considered part of one grouping.