Kalenjin is an ethnic group of Nilotic origin living in the Great Rift Valley in western Kenya and eastern Uganda. The Kalenjin population is estimated at roughly 3 million. There are several smaller tribal groupings within the Kalenjin: Elgeyo, Endorois, Kipsigis, Marakwet, Nandi, Pokot, Sabaot, Terik, Tugen and Sebei.
Until the early 1950s the Kenyan peoples now known as the Kalenjin did not have a common name; they were usually referred to as the 'Nandi-speaking tribes' by scholars and administration officials, a practice that did not immediately come to a halt after the adoption of the common name 'Kalenjin' (cf. Evans-Pritchard 1965). In the late 1940s and the early 1950s, several Nandi-speaking peoples united to assume the common name 'Kalenjin', a Nandi expression meaning I say (to you). Due to this effort, the peoples were transformed into a major ethnic group in Kenya. The Kalenjin make up about 12% of Kenya's population nowadays. The adoption of the name Kalenjin also involved a standardization of the different dialects of Nandi.
The languages of the Kenyan Kalenjin peoples are classified under the linguistic family of Kalenjin languages, which also encompasses languages spoken in Tanzania (e.g. Akie) and Uganda (e.g. Kupsabiny). Due to this even broader use of the term 'Kalenjin', it is common practice in linguistic literature to refer to the languages of the Kenyan Kalenjin peoples as the 'Nandi languages'. The Kalenjin worshipped "Asis" Isis.
The Kalenjin have been called by some "the running tribe." Since the mid-1960s, Kenyan men have earned the largest share of major honors in international athletics at distances from 800 meters to the marathon; the vast majority of these Kenyan running stars have been Kalenjin. From 1980 on, about 40% of the top honors available to men in international athletics at these distances (Olympic medals, World Championships medals, and World Cross Country Championships honors) have been earned by Kalenjin. In recent years, Kenyan women have become a major presence in international athletics at the distances; most of these women are also Kalenjin. It was speculated that the Kalenjin may possess some unique genetic predispositions for running; it seems that their running success results from the combination of their slender physique, slim lower legs, efficient oxygen consumption, and, possibly, the influence of altitude.
The Kalenjin's oral history claim that their ancestors in antiquity were Ancient Egyptians. An example to back this claim, in the oral history resonates with the biblical account of exodus of the Israelites to Canaan. The present day location of the largest sub-nation of the Kalenjin, the Kipsigiis have a river they call River Kipchooryaan or Pchooryaan - which they crossed into the land they now occupy - and a hill they call Tul aap Psigis - which in the Kipsiigis language means "hill of the prolific one", and is the hill they circumcised their men before driving out or assimilating the original owners of the land the Sirikwa and Ogieek.In the biblical account, the Israelites crossed a river they named River Jordan or Yoordan and went up a hill they named Gilgal to circumcise their men before dividind out the land and conquering the Canaanites.
The root to both Pchooryaan and Yoordan in is choor. Choor in Kipsigiis means 'to descend fast' its Hebrew equivalent is yarad or jarad which mean 'to descend', in Coptic - a remnant of Ancient Egyptian language - eiyero means 'river/big canal', hieroglyphs show iaar/itrw for the word river. Derivations for Pchooryaan yields pior (read pyoor) in Coptic and pair (read pyaar) in Ancient Egyptian hieroglyphs - respectively, both words can phonetically interchange to pchoor and pchaar hence Pchoor-yaan. The suffix -yaan in Kipsiigis is a morpheme indicating singular indefiniteness e.g or-aan and or-yaan meaning "path or road" and ash respectively.