Situated in the Tawau Highlands, the mountainous Ulu Kalumpang Forest Reserve is 35 kilometres from Tawau. Covering over 500 square kilometres, the forest reserve is home to a number of endangered species, including the critically endangered orangutan. There are about 183 orangutans in this reserve, isolated from the rest of the world in an attempt to encourage survival. The forest reserve is home to 5 different forest types.