The Keiyo like the rest of the Kalenjin originated from a country in the north known as Emetab Burgei, which means, the hot country. The people are said to have traveled southwards passing through Mount Elgon or Tulwetab Kony in Kalenjin. The Sebeii settled around the slopes of the mountain while the others travelled on in search of better land. The Keiyo and Marakwet settled in present Uasin Gishu plateau, Kerio Valley and Cherangani Hills. The arrival of Warring Uasin Gishu Maasai in the present day Uasin Gishu plateau forced the Elgeyo to move away into the present day Kerio Valley during the expansion of the tribe. The loss of much of their grazing lands forced them to reduce their herds and rely more on agriculture.