The Diocese of the Rift Valley was established in 30 June 1991and covers the Administrative area of the Singida Region which occupies an area of 49,341 square kilometers.  The Region has four districts of which Manyoni is home to the diocesan headquarters.

The present bishop was enthroned in 1992. The Diocese has 234 Churches in 46 Parishes which belong to 10 Deaneries.  They are served by 234 Evangelists ministering to 31,104 Christians.

The Diocese was formed from an area which was originally part of the Diocese of Central Tanganyika. It lies in the central Rift Valley and is crossed by the railway line which runs between the East and West of the country, and the main roads between Dar es Salaam and Mwanza and the North-South route through Itigi to Mbeya.

The region includes a game reserve and so has the potential for tourism. The main activity of the region is farming. Crops include maize, sorghum, groundnuts, sunflower, simsim and millet. There is also livestock rearing including cattle, goats, sheep and donkeys. Unfortunately this area is prone to drought which results in famine.