This reserve was established to protect some of the Big Island’s best wet native forest and unique geologic features. It’s located in the Puna and South Hilo districts.

The wet koa and ‘ohi‘a forest of this Reserve on the northeast flank of Mauna Loa are important habitat for some of Hawai‘i’s rarest birds, as well as several rare plants. A montane wet grassland occurs in the poorly drained portions of the Reserve.