Kenya was the location of some of the earliest human settlements. Sites such as Koobi Fora, near Lake Turkana, indicate hominid habitation dating back 2.5 million years.
In the Kenya highlands, communities that produced their own food by farming and domestication of animals had taken up residence by the end of the second millennium bc. Because of the tools they used, these people—who probably came from the highlands of Ethiopia—are known as the Stone Bowl people. It was not until the last few centuries of the pre-Christian era that other food-producing and iron-working peoples began to take up residence in Kenya. These were the ancestors of the Bantu- and Nilotic-speaking groups of modern Kenya. Bantu-speaking peoples entered Kenya from the west and south, eventually settling east of Lake Victoria, where they occupied land on the coast and in the eastern highlands. The earliest Nilotic-speaking people, ancestors of today’s Highlands Nilotic speakers, entered Kenya from the northwest to take up residence in the highlands west of the Eastern Rift Valley. Later, ancestors of the Plains Nilotic speakers followed, moving into the Rift Valley and the plains to the east. Later still,ancestors of the River-Lake Nilotic speakers moved into the lower-lying regions around Lake Victoria. Eastern Cushitic speakers ancestral to the Oromo moved into northern Kenya from lands to the northeast and were followed by Cushitic-speaking Somali.
This process of migration occurred through small population movements and interactions and stretched over a period of centuries. From this process emerged the various social formations that existed in Kenya at the beginning of colonial rule in the late 19th century ad. These groupings were fluid, representing a process of ongoing social change. For example, in the 17th century the ancestors of the Bantu-speaking Kikuyu settled in the forested hills and ridges south and west of Mount Kenya; as they did so, they borrowed customs from some peoples, absorbed other peoples, and competed with various groups for resources. Most of Kenya’s peoples combined livestock raising with agriculture, although some, like the Nilotic-speaking Masai, were nomadic herders. Unlike nearby regions such as Ethiopia and Uganda, Kenya did not experience the emergence of large, centralized states or empires.