San Antonio Ridge Traverse (Iron Mountain to Mt. Baldy) | TRVRS Outdoors


There are a handful of cross country hikes here in the Southern California Wilderness that push the limits of the word "adventure" for several reasons. They are extremely remote locations that most people will never have the pleasure of seeing. A consequence of their isolated location is that rescue is highly unlikely in the case of an emergency. 

That being said, it is the responsibility of the few that are capable of reaching these locations to practice safety when traveling to these places.

TRVRS Outdoors is all for encouraging new and exciting adventures, but part of the adventure is doing adequate research ahead of time to assure a safe and fun trip which is why we've decided to document these back country hikes. Stay safe!

Directions to the Trailhead

From the 210 Freeway:

  • Take exit 40 for Azusa Ave CA-39 North.
    (The Mobile Gas station on your left is a good place to pick up an adventure pass if you don't already have one.)
  • You will continue on San Gabriel Canyon Rd (Highway 39) for 11 miles until you reach East Fork Rd
  • Make a Right on East Fork Rd and continue for 5 miles until you reach Camp Bonita Rd
  • Turn Left on Camp Bonita Rd and continue .8 miles to the Parking lot at the end of the road.
Alternatively, you can use Google Maps to route you there.


San Antonio Ridge Traverse - OVERVIEW | TRVRS APPAREL

The San Antonio Ridge Traverse is an extremely difficult and desolate cross country hike located almost purely inside of the Sheep Mountain Wilderness of Southern California's Angeles National Forest. The trail starts near Azusa Canyon's Heaton Flat Campground of the East Fork (popularly known for its famous "Bridge to Nowhere" hike) and makes it way up to Iron Mountain. For most, this section is enough of a challenge, as Big Iron is arguably the hardest mountain to climb in the San Gabriel range, and yet, the San Antonio Ridge Traverse continues eastward from this peak toward Mount Baldy, the tallest peak in the Los Angeles County. The trip climbs over 10,000 feet in under 13 miles and includes breath taking views of Mt. Baden Powell, Pine Mountain Ridge, the Cucamonga Wilderness, and essentially all of Southern California. This trek should be reserved for those who have an adequate amount of experience in fitness and cross country adventures.

Here is my account of this route...

East Fork and the Heaton Flats Trailhead

After spending a few minutes re-checking my pack, I locked the car and made a move for the trailhead. I packed 2.75 liters of water, a can of coconut water, a homemade turkey club wrap, one apple, one banana, and a few random energy bars. I was good for at least 20 miles.

3:38 am - Thanks to a quick stop at the gas station for an iced coffee, I left the East Fork parking area feeling pretty good especially after only having slept an hour and a half. Within a few moments, I started jogging. The dumb part of meof me knew that if I kept up a strong pace, I'd make it up to Iron before sunrise. The less dumb part knew that I should focus on reserving my energy since I would need it later. I ended up finding a happy medium and a half mile later, I reached Heaton Flat Campground and its big wooden sign featuring a map of most of the Sheep Mountain Wilderness. I continued onto the Heaton Flat trail head, which is obscurely located behind this sign.

Entering the Sheep Mountain Wilderness

4:15 am - (2 miles, 1,100 feet climbed) -- I reached the unnamed saddle (marked 3,042 on the map) and took a short break to de-layer; then continued North. Within a hundred feet, I ran into the infamous sign that says "Entering Sheep Mountain Wilderness".  This meant that the first goal was complete and all that was left was to exit the Sheep Mountain Wilderness through the other side. Easy-peasy.

Shortly after passing the sign, the trail made a quick switchback which brought me to the top of some rolling hills and clear views of the Iron Mountain to the North. It would be another mile before I dropped down into Allison Saddle (4.3 miles, 4,600 feet climbed). Every other time I had done this hike with groups, we would take a nice long break here and for good reason. Allison saddle features a small, shaded nook perfect for a 4-6 person hiking group to drop their bags and enjoy a small snack. It also happens to be located just before the real ascent begins.

Bagging Big Iron

5:15 am - The three miles following Allison Saddle would include 3,400 feet of vertical gain with the bulk of that being on the front end. At the time of writing, this section was more difficult than it is today (edited 03/13/2022). What was once the Iron Mountain route including a ton of steep loose dirt and scree in which you would need to use your hands to ascend is now a walkable trail. This is not to say that summiting is not an accomplishment. However, this trip report has become somewhat of a guide as the years have gone by and I figured I should include updates for those who intend to make the ascent.

By the time I reached mile five, the ascent became more gradual and I was actually able to enjoy the views. South Hawkins and Rattlesnake peak swept in over the East Fork San Gabriel River, while the Southwest ridge of Iron pulled me into focus with intrigue. Mount Baldy loomed over the San Antonio Ridge, but I highly recommend not looking over this way if you intend to complete the traverse and have any sort of doubt at this point.

6:50 am - I made it to Iron Mountain's summit just in time to watch the sun rise over Mount Baldy. This couldn't have been timed better because I would have been nervous about continuing along the ridge in the dark. I took a short break to collect myself, refuel, and add a layer of clothing to the mix. The time for speed had passed. The next two miles would be very slow going.

After taking a few pictures and eating half of a turkey bacon wrap, I began to descend along the ridge route. Within 5 minutes, I was already using my hands to down climb small exposed sections. I had to stop several times to slow my heart rate, which I blame mostly on coffee and adrenaline, but this was definitely an odd experience for me. felt...anxious?

In hindsight (as I am reading this in 2022) this was probably due to my lack of sleep and adrenaline catching up to me. In years following this endeavor, I would have this same experience on many climbs where altitude, adrenaline and sleep deprivation simply weren't a good mix for me. I eventually learned to manage it by taking naps in some very interesting places.

This trend of down climbing loose granite continues for the entirety of mile 8 and the hardest part was saved for last.

Gun Sight Notch

San Antonio Ridge Traverse - Gun Sight Notch | TRVRS APPAREL

The sick name alone begs for this section to have its own paragraph. Apparently it gets its name from its similarity in shape to a gunsight, which in all honesty could probably be said about any ridge spur...This is almost as original as the name Strawberry Peak because its "striking" resemblance to a strawberry, but I digress.

Gun Sight Notch is the final and probably the most difficult class 3 exposed descent you will deal with on the SART (San Antonio Ridge Traverse). However, if you look closely and take your time, you'll realize the best route is straight down from the top (facing east) and success should come with relative ease. I made it past Gun Sight Notch  and continued toward the second peak of the day, but not without looking back after I was done. Its quite view from the bottom and knowing that I completed it gave me a little extra confidence for what was to come.

Ascending Mount Baldy
San Antonio Ridge Traverse - Rolling Hills | TRVRS APPAREL

I should note that after Gun Sight notch, you'll still have two large rolling hills to climb before the final ascent. Both of which cover a grand total of 2 miles with about 800 feet of vertical gain. In most cases, this would probably have been a nice jog for me, but the coffee had worn off, the energy from the last meal was spent, and the route, which stays mostly on the north side of the ridge, was covered in ice. I kept trying to avoid the ice by going around the south side of the ridge only to find myself surrounded by chaparral and Manzanita.

San Antonio Ridge Traverse - Mount Baldy Base | TRVRS APPAREL

9:30 am - By the time I had finally reached the base of Mt. Baldy, I was burned out again. I took a short break to load up on sugar and attach my crampons. This was my first time using both crampons and an ice axe, and even though I had spent a good amount of time researching their optimal use, I was at first terrified that I'd end up sliding down the mountain. After taking only a few steps, I was laughing at how easy it was for me to climb directly up to the peak. I opted for the north-west aspect over the ridge because there was more solid packed snow and less rock. I was in heaven. No switchbacks, and no trail to follow. Just pure ascent. 

[I think its important to mention that even though I had brought equipment I had never used on a route that could be seen as extremely dangerous, I was very well aware before leaving that I'd likely turn around at this point. I mentioned this to all of my emergency contacts before leaving. I had no intention of doing something I wasn't comfortable with]. 

San Antonio Ridge Traverse - West baldy | TRVRS APPAREL

11:30 am - (11.5 miles, 9,500 feet) I felt completely drained by the time I reached West Baldy and wondered if a slower pace would have granted me better endurance. From this pseudo-peak, Mount San Antonio still looked far away, but the bulk of the climbing was done and I knew I was less than a mile from the summit. Success was now immanent.

The Devils Backbone

San Antonio Ridge Traverse - Mt. Baldy Summit | TRVRS APPAREL

I spent a few minutes trying to wave down commercial airlines for rescue, then decided that I would continue down the Register Ridge trail to get back home as fast as possible. I made my way down the east slope of Baldy. Fortunately, about 200 feet  before I reached the trail junction, I saw three strangers coming up the trail. Without hesitation, I asked them whether or not the Ski Lift was open. IT WAS!

So instead of taking the steep knee buster route back to the car, I continued to stumble down the rest of the Devils Backbone trail toward the Top of the Notch Restaurant where I bought a lift ticket.


I was in the clear. The Bartender must have noticed how thrashed I looked when he asked me about the hike. I let him know that I started in Azusa Canyon. He paused for a second trying to figure out how the two areas connected. So I gave him a brief description of the journey and he congratulated me, noting that it was the furthest he had heard of anyone hiking from. I chuckled and thought of all the ultra runners I knew who had completed the 11-peak traverse. Maybe, one day...

 Elevation Profile

Total Distance (to peak): 12.2 miles
Total Elevation (feet):
10,056 feet
Time to completion: 8 hours, 30 minutes (East Fork Parking lot to Mt. Baldy Summit)

***If you are planning to complete this hike, please be aware that this is definitely a fast time. I have trained as a trail runner for several years. The first time I completed it with a strong group of hikers and finished in just over 14 hours from car to car. This is a much more realistic time for a group.


San Antonio Ridge Traverse - GPX FILE

San Antonio Ridge Traverese - STRAVA ACCOUNT


  • Cher

    There’s nothing quite like the notches of the ridge, basically terrifying and exciting all at the same time. I personally underestimated this hike having felt confident just hiking C2C. The other comment was correct C2C seems like a walk in the park.

  • Steve Anderson

    A climbing partner and I did this great traverse back in 1977. We didn’t know what we were getting into on this adventure. By the time we reached the west Baldy summit it was already dark and we goofed when we went down the wrong way and by some miracle were able to connect with the Baldy Ski Lift road. Your write up about the obstacles is right on!

  • Hans Linnemann

    So started this traverse at Heaton Flats up to Iron in 6 hours. The Ridge was insane 3 tricky exposed climb downs . Gun Sight notch was super hard. Took about 6 hours to complete the ridge. Back side of Baldy is like Iron Mountain all over again . About 5 hours climb. Super tough all around. After completing this trek Catus to Clouds will be a walk in the park .

  • Richard Vargas

    My son James Vargas went on the big big hike today it’s already 840pm have not heard anything do you know what is going on with him and the rest of the group today is June 2nd 2018 please email me

  • Manny Herrera

    This sounds amazing. I want to do this sometime soon but would love to go with someone who has completed it before.

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