From the Wikipedia page 
Kilosa District is one of the six districts of the Morogoro Region of Tanzania. Its administrative seat is the town of Kilosa. Kilosa District covers 14,918 square kilometres (5,760 sq mi). It is bordered to the north by the Manyara Region, to the northeast by the Tanga Region, to the east by Mvomero District, to the southeast by Morogoro Rural District, to the south by Kilombero District, to the southwest by the Iringa Region and to the west by the Dodoma Region.