From Halopedia, the Halo wiki
Arusha is a city in Tanzania, Africa on the planet Earth. It is reachable on Tsavo Highway, which links it to Mombasa and Voi. Arusha is 134 kilometers from Checkpoint 8, and 148 kilometers from Traxus Factory Complex 09. In a traffic sign on Tsavo Highway, Arusha is crossed out, meaning either the highway leading there is unsurvivable, or the entire city has been occupied or destroyed.