The administrative divisions of Tanzania are controlled by Part I, Article 2.2 of the Constitution of Tanzania. Tanzania is divided into thirty regions (mkoa in Swahili). Each region is subdivided into districts (wilaya in Swahili). The districts are sub-divided into divisions (mgawanyiko in Swahili) and further into local wards (wodi in Swahili). Wards are further subdivided for management purposes: for urban wards into streets (mitaa in Swahili) and for rural wards into villages (kijiji in Swahili). The villages may be further subdivided into hamlets (vitongoji in Swahili).
More information on the Wikipedia page .