Engaruka is an abandoned system of ruins located in northwest Monduli District in central Arusha Region. The site is in geographical range of the Great Rift Valley of northern Tanzania. Situated in the Monduli District, it is famed for its irrigation and cultivation structures. It is considered one of the most important Iron Age archaeological sites in Tanzania. The site is located in the ward of Engaruka. The site is registered as one of the National Historic Sites of Tanzania. The site Sometime in the 15th century, an Iron Age farming community built a large continuous village area on the footslopes of the Rift Valley escarpment, housing several thousand people. They developed an intricate irrigation and cultivation system, involving a stone-block canal channeling water from the Crater Highlands rift escarpment to stone-lined cultivation terraces. Measures were taken to prevent soil erosion and the fertility of the plots was increased by using the manure of stall fed cattle. For an unknown reason Engaruka was abandoned at latest in the mid-18th century. The site still poses many questions, including the identity of the founders, how they developed their farming system, and why they left. Construction of Engaruka has traditionally been credited to the ancestors of the Iraqw, a Cushitic-speaking group of cultivators residing in the Mbulu Highlands of northern 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 Datoga, herders who are known to have occupied the Crater Highlands above Engaruka prior to the arrival of the Maasai. This population movement is reportedly consistent with the date of the Engaruka site's desertion, which is estimated at somewhere between 1700 and 1750. It also roughly coincides with the start of the diminishment of the Engaruka River's flow as well as those of other streams descending from the Ngorongoro highlands; water sources around which Engaruka's irrigation practices were centered. According to the Maasai, who are the present-day occupants of Engaruka, the Iraqw also already inhabited the site when their own ancestors first entered the region during the 18th century. Engaruka has also been linked to the Sonjo, a numerically small Bantu-speaking living