Mara Region is one of Tanzania's 31 administrative regions. The region covers an area of 21,760 km2 (8,400 sq mi). The region is comparable in size to the combined land area of the nation state of El Salvador. The neighboring regions are Mwanza Region and Simiyu Region, Arusha Region, and Kagera Region. The Mara Region borders Kenya .The regional capital is the municipality of Musoma. Mara Region is known for being the home of Serengeti National Park, a UNESCO World Heritage site and also the birth place of Tanzania's founding father Julius Nyerere. Under British colonial occupation, the Mara Region was a district called the Lake Province, which became the Lake Region after independence in 1961.

Mwanza Region is one of Tanzania's 31 administrative regions. The region covers a land area of 25,233 km2 (9,743 sq mi). The region is comparable in size to the combined land area of the nation state of North Macedonia. Mwanza Region is bordered to the north through Lake Victoria by the Kagera Region and Mara Region, to the east by Simiyu Region, to the south by the Shinyanga Region and to the west by Geita Region. The regional capital is the city of Mwanza. According to the 2022 national census, the region had a population of 3,699,872 and national census of 2012 had 2,772,509. Mwanza Region is the second region with high population in Tanzania after Dar es Salaam Region.