By the 1st century CE, many of the city-states such as Mombasa, Malindi, and Zanzibar began to establish trade relations with Arabs.

This led to the increase economic growth of the Swahili states, introduction of Islam, Arabic influences on the Swahili Bantu language, cultural diffusion, as well as the Swahili city-states becoming a member of a larger trade network.

The economy of Kenya is the largest by GDP in East and Central Africa.

The capital, Nairobi, is a regional commercial hub.

During excavations at Lake Turkana in 1984, paleoanthropologist Richard Leakey assisted by Kamoya Kimeu discovered the Turkana Boy, a 1.6-million-year-old fossil belonging to Homo erectus.

Previous research on early hominids is particularly identified with Mary Leakey and Louis Leakey, who were responsible for the preliminary archaeological research at Olorgesailie and Hyrax Hill.

Later work at the former site was undertaken by Glynn Isaac.

During the early Holocene, the regional climate shifted from dry to wetter climatic conditions, providing an opportunity for the development of cultural traditions, such as agriculture and herding, in a more favourable environment.

Many historians had long believed that the city states were established by Arab or Persian traders, but archeological evidence has led scholars to recognize the city states as an indigenous development which, though subjected to foreign influence due to trade, retained a Bantu cultural core.

The Kilwa Sultanate was a medieval sultanate, centred at Kilwa in modern-day Tanzania.

Bantu groups in Kenya include the Kikuyu, Luhya, Kamba, Kisii, Meru, Kuria, Aembu, Ambeere, Wadawida-Watuweta, Wapokomo and Mijikenda among others.

Remarkable prehistoric sites in the interior of Kenya include the archaeoastronomical site Namoratunga on the west side of Lake Turkana and the walled settlement of Thim Lich Ohinga in Migori County.

Further inland are highlands in Central and Rift Valley regions where tea and coffee are grown as cash crops which are major foreign revenue earners.