From the Wikipedia page 
Mara Region is one of Tanzania's 31 administrative regions. The regional capital is the municipality of Musoma.
The neighboring regions are Mwanza Region and Simiyu Region (to the south), Arusha Region (to the southeast), and Kagera Region (across Lake Victoria). To the northeast, the Mara Region borders Narok County and Migori County in Kenya. The Mara Region is the home of Tanzania's first president, Julius Nyerere. The Mara Region was also the birthplace of Benga music.