Lake Bogoria is a saline, alkaline lake that lies in a volcanic region in a half-graben basin south of Lake Baringo, Kenya, a little north of the equator. Lake Bogoria, like Lake Nakuru, Lake Elmenteita, and Lake Magadi further south in the Rift Valley, and Lake Logipi to the north, is home at times to one of the world's largest populations of lesser flamingoes. The lake is a Ramsar site and has been a protected National Reserve since November 29, 1973. Lake Bogoria is shallow (about 10 m depth), and is about 34 km long by 3.5 km wide, with a drainage basin of 700 km².
Local features include the Kesubo Swamp to the north and the Siracho Escarpment to the east, both within the National Reserve. The reserve is also famous for its geysers and hot springs.
The lake waters are of Na-HCO -CO composition. They originate from inflow from the Sandai and Emsos rivers, and from about 200 alkaline hot springs that are present at three onshore sites: Loburu, Chemurkeu, and a southern group (Ng'wasis, Koibobei, and Losaramat). Other springs discharge directly from the lake floor. Lake Bogoria also contains the highest concentration of true geysers in Africa (at least 18 are known). The lake waters are alkaline (pH: 10.5) and saline (up to 100 g/L Total Dissolved Salts). The lake has no surface outlet so the water becomes saline mainly through evaporation, which is high in this semi-arid region. The lake itself is meromictic (stratified) with less dense surface waters lying on a denser more saline bottom waters. Although hyper saline, the lake is highly productive with abundant cyanobacteria (Arthrospira fusiformis) that feed the flamingoes, but few other organisms inhabit the lake.