Consisting of 4,760 acres (19.3 km2) in Riverside County, California, west of Morongo Valley, the preserve features perennial Mission Creek flowing through a desert canyon.

It is located within the San Bernardino Mountains and is part of the Sand to Snow National Monument.

Just past the gate are the remains of an old tourist ranch with four stone cabins, each with a picnic table inside.

Hikers can walk on the dirt road to the Stone House Campground, passing a densely vegetated wetland.

An interpretive program for kids focuses on desert water cycles and watershed ecology.

The preserve is surrounded by the Bureau of Land Management's San Gorgonio Wilderness and is within the Sand to Snow National Monument.

In August 2023, remnants of Hurricane Hilary dumped 13.07 in (332 mm) of rain in Upper Mission Creek.