[3] It has semi-tropical vegetation on the slopes, while the floor of the valley is covered by dry thorn bushes.

[4] The Kerio Valley is the site of elaborate irrigation systems that were constructed during earlier periods of history.

These structures are believed to have been built by descendants of the Neolithic Afro-Asiatic people who introduced domesticated plants and animals to the Great Lakes region[6]—a succession of societies collectively known as the Stone Bowl cultural complex.

Although the particular irrigation systems in the Kerio Valley are today maintained by the Marakwet subgroup of the Kalenjin Nilotes, the latter assert that they were the work of a northern people of a peculiar language called the Sirikwa, who were later decimated by pestilence.

In Kimwarer in the southern part of the valley, fluoride is mined by the Kenya Fluorspar Company.