From the Wikipedia page 
Mbarali District is one of the seven districts of Mbeya Region, Tanzania. It is bordered to the north and east by Iringa Region, to the south by Mbeya Urban District and to the west by Chunya District.
According to the 2002 Tanzania National Census, the population of Chunya District was 234,908. Before the expansion of the Ruaha National Park in 2008, Mbarali District covered an area of 15,560 square kilometres (6,008 sq mi)