Before independence, Iraqw villages varied greatly in size, ranging from 40 to 400 inhabitants. Since 1974, the Iraqw have been moved into eighty-six villages in Mbulu District. In the northern part of the district, the villages have an average population of 2,500 people in 400 households. In the southernmost part of Mbulu, the villages average 1,500 people in some 225 households. The household typically consists of a man, his wife, and their children. It is the primary economic unit: each has its own agricultural plots and livestock. Every village is named and has a definite boundary. Houses within the village are dispersed.
House types vary by geographical conditions within Mbulu District. There are three basic types of houses. The subterranean house, which is dug into the side of a slope and has an earthen roof, was thought to be built as a defense against raids by the Maasai. Another type, which is most common in Mbulu District, is the round, grass-thatched and mud-plastered house. These houses have a small entryway and, usually, no windows. Most houses face west. Inside, the house is divided into rooms and there is a sleeping platform covering part of the main living space. Immediately inside the entryway is a room where the livestock are brought for the night. Outside the entrance is a courtyard of packed earth. A Swahili-style dwelling has appeared in Mbulu, and it is being encouraged by the Tanzanian government. Square or rectangular, its peaked ridge roof is of thatch or sheet metal, and it has several windows.