This article examines the origins of the Samburu people of northern Kenya. It puts the relatively recent development of the Samburu, assuming a common identity, into historical context and argues that one can best understand the pastoralists’ ethnogenesis by examining a host of complex and dynamic variables. The authors emphasize the significance of environmental factors, as well as the Samburu's interactions with neighboring ethnic groups, for their coming into being as a distinct community and argue that only by critically analyzing a variety of sources can one gain a clear understanding of events for which there is a paucity of reliable written documentation. Thus, this work traces the history of human habitation in the East Lake Turkana Basin from its beginnings through the nineteenth century. This study compares the oral histories of the inhabitants of the region and includes information derived from sources drawn from comparative linguistics, comparative material culture, and the early written accounts of outsiders to reconstruct the past and explore how proto-Samburu groups adopted a common identity. The authors also address how major developments among neighboring ethnic groups (namely, the collapse of Oromo and Maasai hegemony and the arrival of large numbers of Turkana and Somalis) influenced the Samburu. Finally, the article addresses the nature of the Samburu institutions and how pastoralists exploited the environment for their sustenance in the early years of their existence.