Keiyo District (also known as Elgeyo district or Elgeiyo) is a defunct administrative district in the former Rift Valley Province of Kenya. The district was formed in 1994, when Elgeyo/Marakwet-District was split into two - the other half was Marakwet District. Keiyo District had a population of 143.865 [1]. Its capital was located in the Iten/Tambach town.