The Kilombero Valley is the largest seasonal wetland in East Africa. It is split into 2 districts, Kilombero and Ulanga, by the Kilombero River.
It is home to several species of endemic birds (including the Kilombero Weaver), the only sustainable population of Puku (Kobus Vardoni - a large rare antelope) and a formerly high concentration of lions though this is in decline due to habitat destruction.