[3] The Iraqw people then settled in the southeast of Ngorongoro Crater in northern Karatu District, Arusha Region, where the majority of them still reside.
[4] The Iraqw have traditionally been viewed as remnants of Afro-Asiatic peoples who practiced agriculture and animal husbandry in the Great Lakes region[5] — a succession of societies collectively known as the Stone Bowl cultural complex.
Although these particular structures are today maintained by the Marakwet subgroup of the Nandi Kalenjin Nilotes, the latter aver that they were the work of a northern people of peculiar language called the Sirikwa, who were later decimated by pestilence.
Additionally, the Iraqw's ancestors are often credited with having constructed the sprawling Engaruka complex in Monduli District, Arusha Region, Tanzania.
The modern Iraqw practice an intensive form of self-contained agriculture that bears a remarkable similarity to the ruins of stone-walled canals, dams and furrows that are found at Engaruka.
Iraqw historical traditions likewise relate that their last significant migration to their present area of inhabitation occurred about two or three centuries ago after conflicts with the Barbaig sub-group of the Datog Nilotes, herders who are known to have occupied the Crater Highlands above Engaruka prior to the arrival of the Maasai.
A Y-chromosome study by Wood et al. (2005) tested various populations in Africa for paternal lineages, including 9 Iraqw males from Tanzania.