Nanjirinji is an administrative ward in Kilwa District of Lindi Region in Tanzania. The ward covers an area of 3,733 km2 (1,441 sq mi),[1] and has an average elevation of 224 m (735 ft).[2] According to the 2012 census, the ward has a total population of 7,491.[3] The ward seat is Nanjirinji village.[4] Nanjirinji ward is also the source of the Mavuji River.