Arusha Region is one of Tanzania's 30 administrative regions. Its capital and largest city is the city of Arusha. The region is bordered by Kajiado County and Narok County in Kenya to the north, the Kilimanjaro Region to the east, the Manyara and Singida regions to the south, and the Mara and Simiyu regions to the west. Major towns include Monduli, Namanga, Longido, and Loliondo to the north, Mto wa Mbu and Karatu to the west, and Usa River to the east. The region is comparable in size to the combined land and water areas of the United States state of Maryland.
Arusha Region is a global tourist destination and is the center of the northern Tanzania safari circuit. The national parks and reserves in this region include Ngorongoro Conservation Area, Arusha National Park, the Loliondo Game Controlled Area, and part of Lake Manyara National Park. Remains of 600-year old stone structures are found at Engaruka, just off the dirt road between Mto wa Mbu and Lake Natron.