With almost 28,000 square kilometers, Ruaha is the largest national park in Tanzania and serves as the country's central ecosystem. The park owes its name to the Great Ruaha River, a massive river that flows southeast through its heart and has to give way to a hilly plateau, sand rivers, rock formations and baobab groves. The Ruaha National Park is characterized by a mixed zone between the East African savannas and the South African Miombo forests, creating an overlapping variety of plant and animal species in the Rungwa and Usanga game reserves.