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Milpitas Wash Wilderness

Features: S. 47, the John D. Dingell, Jr. Conservation, Management, and Recreation Act, protected over 375,000 acres of new wilderness areas in the California desert in March 2019. One of those places is the Milpitas Wash Wilderness in eastern Imperial County just west of the Colorado River.

Milpitas Wash is a very large seasonal desert stream that drains east into an even larger wash and then into the Colorado River. The region supports the largest Sonoran Desert woodland in North America. Most of the trees are legumes, members of the pea family: mesquites, acacias, palo verdes, and ironwoods; and there are also desert willows. The abundance of old-growth trees, with most standing over 15 feet high, gives the area a lush character rarely found in the desert.

The Milpitas Wash provides critical habitat for desert tortoise, mountain lion, long-eared owl, leaf nose bat, Merriam and desert kangaroo rat, long tail and little pocket mice, Bullock’s and hooded orioles, towhees, white-crowned sparrow, Brewer’s sparrow, warbler, black-headed grosbeak, diamondback rattler, and the endangered Gila woodpecker. A small subspecies of mule deer known as burro deer also lives here. The burro deer is California’s least common deer, but hoof prints of the creature abound in Milpitas Wash.

The area has no trails, so visitors must make their own way cross-country through this rugged but fairly level landscape. The easiest walking is on hardpan soils known as “desert pavement.” This blackish-orange soil type alternates at Milpitas Wash with the eroded banks of side-washes that feed into the main channel of Milpitas Wash. While desert pavement appears lifeless at first, we are just coming to understand that this soil type stores immense amounts of carbon and it is knitted together with fungi, similar to a forest.

The area’s wildflowers can be amazing in spring, and the views of the Palo Verde Mountains Wilderness to the north are outstanding.

Driving Directions: From Interstate 10 west of Blythe in Riverside County, take State Highway 78 south for 28 miles to Milpitas Wash Road on your right. Turn right and drive west for roughly 1.5 miles until you pass a powerline running north to south. The Milpitas Wash Wilderness is south of Milpitas Wash Road and west of the powerline. Park anywhere after the powerline, walk south from the Milpitas Wash Road, and enjoy the new Wilderness!


Caution: Weather and road conditions can change in an instant. Always check with the managing agency before embarking on a trip. Always hike with a friend and carry a cell phone for emergencies. Bring plenty of drinking water, food, and clothing for changing weather conditions. Let someone know where you are going and when you intend to be back. Remember, California’s wild places are beautiful but they can also be dangerous to the unprepared and unwary. The California Wilderness Coalition assumes no liability if you intend to visit any of the wild places featured in our materials.