Waimānalo Forest Reserve is located at the Northwest end of Waimānalo Valley, windward Oʻahu. The WFR, which occupies nearly 500 acres, is forested by invasive species, primarily Acacia confusa (Formosan Koa), Falcataria moluccana (Albizia), and Schefflera actinophylla (Umbrella Tree). Forest cover is complete in majority of the forest reserve. Animal life in the forest reserve primarily consists of invasive birds, rodents, and similar small mammals.

Located within this forest reserve is Mount Olomana which has been established as a historical landmark by the Department of Land and Natural Resources due to its' visual, cultural, and historical aspects and significance.