From the Wikipedia page 
Tabora Region is one of Tanzania's 31 administrative regions. The regional capital is the municipality of Tabora.
The region is in the central-western part of the country. It is bordered to the north by Shinyanga Region, to the east by Singida Region, to the south by Mbeya Region, to the southwest by Katavi Region, to the west by Kigoma Region, and to the northwest by Geita Region.