Childs Mountain

Development Route / by Captain ‘O’

Note: This is a Development Route, meaning that it is a work in progress and currently does not meet the Dirty Freehub 5 Star standard for great routes.

A simple out & back to the radar installation atop Childs Mountain. The site is historically significant for the cold war military installation that was there. The site is also noteworthy for the great views of the Growler Mountains and the expansive Sonoran desert, especially at sunrise and sunset.

The Ajo Radar Station, located on Childs Mountain, was constructed by the U.S. Air Force from 1956 to 1958. Operations at the station were terminated in 1971, and the facility was abandoned the following year. The current radar station, often referred to as the golf ball, was constructed in 1998.”[Cabeza Prieta Natural History Association]

We have worked with Cabeza Prieta National Wildlife Refuge to gain access for biking. However, you must acquire a special use permit to ride the route. The details of the permit application are described below. We are also working with the Refuge to gain access to other roads for biking. By being good stewards of the places we ride, our case for greater access is enhanced.

We have classified this as a Development Route because a member of Team Dirty Freehub has not ridden th route and we don’t have a full set of pictures. But … we believe it is of 5 Star quality.

If you do the ride and have some pictures or comments to share, we would love to hear from you. Our email address is at the bottom of the page.

Adventure / Gravel Route

Out & Back: 17 miles / 1700 ft gain
– Surface: ~ 60% gravel, 15% Roubaix (broken pavement), 25% paved
eBike Friendly: Yes
– Location: ~ Tucson, AZ
– Published: February 2021

Technical Difficulty & Risk[what this means]

Moderate- (Overall)

  • Technical Riding Difficulty: Moderate-
    Much of the route is old, broken pavement. There even a section of new pavement. The steepest pitches are 6 to 8%.
  • Navigation Challenge & Risk: Low
    The only turns are near the summit, to the radar installation or Larue Benchmark.
  • Remote Risk: Moderate-
    With the cessation of activities at the border wall, the area could have little activity.

When we like to ride this …

Fall through spring. Summer could be hot and exposed.

Please note, a special use permit may is required to bike beyond the gate at ~ mile 3. The permit is issued by the Cabeza Prieta NWR headquarters and normally takes 48 hours to process. Contact Alfredo Soto (Wildlife Refuge Specialist) at (520) 387-4987. Mention that you want to ride the Childs Mountain route posted on Dirty Freehub.

The Start

A makeshift dirt parking area along the north side of the road to Childs Mountain.
Lat / Long: 32.447426, -112.872455

Go Local!

After your ride, drop some coin at one of the restaurants in the Ajo Town Plaza, or better, come to Ajo and make a long weekend of it. Arts, culture, and riding! What could be better? You can find more information on where to eat, where to stay, and what to do at Ajo – Local First Foundation, Visit Arizona, and the Ajo Chamber of Commerce. Also, a great Instagram feed to follow is VisitAjo.

For help with GPS files, the RideWithGPs mapping app and to learn how to download our routes for free, see the “Using Our Rides” page.


Red = paved road
Brown = gravel / dirt road
Purple = broken pavement / roubaix

Ride Details

“Childs Mountain, located almost 1,500 feet above the desert floor (2,800 feet above sea level), offers a panoramic view of the surrounding Sonoran Desert, including parts of Cabeza Prieta National Wildlife Refuge (to the west) and the Barry M. Goldwater Air Force Range (to the north). Childs Mountain is an uplifted, old lava flow. The substrate on the mountain is composed of shallow, clay silts and caliche nodules can be noted.”[Cabeza Prieta Natural History Museum]

From the start, head west on a gravel road across the desert plain. The first 2.5 miles are relatively flat. Along the way [~ mile 2.3], you pass by the old barracks site of the defunct Ajo Air Force station. 

The original barracks site.
(Photo Credit: Cabeza Prieta Natural History Association)
The site today.
(Photo Credit: Cabeza Prieta Natural History Association)

The Childs Mountain radar station was established in January 1958 and became operational in 1958 as Ajo Air Force Station manned by the 612th AC&W Squadron. The station initially had both a Ground-Control Intercept (GCI) and early warning mission. The early warning mission involved tracking and identifying all aircraft entering their airspace, while the GCI mission involved guiding Air Force interceptors to any identified enemy aircraft. Controllers at the station vectored fighter aircraft at the correct course and speed to intercept enemy aircraft using voice commands via ground-to-air radio.

Abandoned as an Air Force Station 1969 and left to the elements. The station’s 27 housing units were removed to Gila Bend. In 1994 most of the remaining site buildings were torn down, and the site was restored to a natural state by the National Park Service. Only the FPS-26 radar tower remained with the Air Force and FAA maintaining some equipment supporting the Luke-Williams range and radio relay equipment. The upper site was taken over by the FAA in 2000 as a Joint Use radar site and currently has an ARSR-4 3D radar installed. [FortWiki]

The road then bends south and starts up a moderate grade, then makes a long bend north again, at the base of the day’s first steep slope, ~ 6% grade. The road is gated here, at about mile 3.3. The next 2 miles climb 600 feet.

At mile 5.4, you come to a flat respite in the climb. The middle section was the cantonment for 100 to 200 troops stationed at the radar installation. It included administrative buildings, dormitories, a post exchange, a gymnasium, and even a swimming pool. The buildings, including the concrete slabs, have been removed. Thus, leaving little visible evidence of the old base.

The cantonment site. Looking east, from above on the road.
(Photo Credit: US Fish & Wildlife Service)

The route continues to climb for 0.6 miles until a Y junction. The left fork (south) leads to the current day FAA white-domed radar [paved, 0.7 miles, and 300 feet of gain], which is worth taking a peek at. The right leads out to Larue Benchmark [gravel, 1.3 miles, 300 feet of gain], where there are some interpretive signs and great views!

“I looked out west across the desert at the Growler Mountains and miles and miles of open Sonoran Desert. The views were wonderful. I looked east and all the ranges that way — Sauceda, Batamote, Pozo Redondo, and those surrounding Ajo the town. I could see the spire of Kino Peak way off to the south and the rounded hump of Woolsey Peak north by Gila Bend.” Scott Surgent.

After enjoying the views, turn around and zip back to the start. Now, the most important part. Go visit the town of Ajo! For a bite to eat, visit the Town Plaza. Or maybe wander up to the old mining facility overlook. Or walk the town looking at the mural art.

Food / Water


Researched by …

Captain ‘O’ (Aka: KevinE) / Team Dirty Freehub

He should have “Never Stop Exploring” tattooed on his chest! He loves adventures on bikes and is a Co-Founder of Dirty Freehub.

Scroll to Top