The Gomantong Caves are an intricate cave system inside Gomantong Hill. The hill is the largest limestone outcrop in the Lower Kinabatangan area, Sandakan division, in the Malaysian state of Sabah, on Borneo island. Situated in a Sabah Forestry Department forest reserve, the caves and the surrounding area are a protected area for wildlife, especially orangutans. The limestone hill is also the only known site for the endangered land snail Plectostoma mirabile. Investigation of the guano deposits were first made in 1889 by J.H. Allard of the China Borneo Company, and the caves were first mapped by P.