Heaton Flat Trail to Iron Mountain

HARD 98 reviews
#30 of 215 trails in

Heaton Flat Trail to Iron Mountain is a 12.6 mile moderately trafficked out and back trail located near Azusa, California that features beautiful wild flowers and is rated as difficult. The trail is primarily used for hiking, walking, nature trips, and birding and is accessible year-round. Dogs are also able to use this trail.

12.6 miles
6,338 feet
Out & Back

dog friendly


nature trips


bird watching



wild flowers


Directions from Azusa, CA: Travel north on Highway 39 for about 12 miles, turn east (right) onto East Fork Road and travel 6 miles. Entry is from the East Fork Trailhead adjacent to East Fork Fire Station.

3 days ago

Bummer my recording was deleted 3.5 miles in at 2500 vertical gain so it’s 6800 total for vertical. It was actually really amazing hike. One of the toughest I have done, last 500 feet was all snow. But wow what a view. If your up for the challenge this one gives it and reminds you as your descending that you have more elevation gain. So yeah this one beats all others for pure pain on the knees.
It was much easier than I expected, But the worst part of it was the decent for sure.
Bring your poles, your knees will thank you.

By the way was reading some of the low rated reviews, seriously

5 days ago

Snow 2 miles from the top as of 3/13. Doable but extremely dangerous.

4.08 miles 2:38:03 1016ft ascent

29 days ago

Amazing. Narrow and slick in spots but the views are worth it!

1 month ago

This is not a hike for amateurs. Youtubers, earbud jockeys, and dog walkers stay home. One must pay full attention during this challenge. Heed my warning one misstep, slip, or loss of balance will put you in a world of hurt or in a coma. If they locate your body it maybe too dangerous to recover for weeks due to the topography and weather conditions. If you're unfortunate to live it will be a long hobble back to base including an impromptu night camp in frigid temperatures and exposure because you started this baby in the afternoon. If you have the nuts and want to test the limits of your physical and mental endurance this is the hike for you. Start as early as possible. Check the weather conditions. Give someone your itinerary and expected return time. I do not recommend this hike solo. Bring an experienced friend. We started this one at 7 am and reached the base of iron mountain by 11:30 am. There were no other hikers on this trail during the ascent. 1 mile away from the summit we had to turn back. The picturesque views of snow capped mountains under partly sunny sky's turned quickly. The clouds rolled in temperatures dropped and it began to snow. All fun and good till it was a whiteout. As we slowly descended the steep crags the winds picked up making it even more frigid. The lower our altitude the warmer it became. A mixed blessing as snow turned to hale then to sleet then to rain. Soaking wet and spent we reached the parking lot without an injury at 4 pm. Maybe winter wasn't a good time to tackle the iron giant? We attempted February 10th. Come spring time we'll be back.

3 months ago

I did this hike just after it rained in the first week of December. When I got up to 6000’ or so there was about 6” of snow and roughly a foot at the summit!!

Couldn’t have picked a better time to hammer out this hike! Highly recommended!!

I was able to get to the summit in 3hrs and 45mins.

Round trip was 7.5hrs total including some breaks and 20mins at the summit.

4 months ago

The views on the way up and especially at the top are simply outstanding. Overall this is a much easier hike than C2C, but the long steep ascent is total murder on the legs. Quads in particular get hit quite hard. Hiking poles would probably help give the legs a break. Going back down is a little tricky in spots, due to the loose sand and rocks, but nothing careful foot placement (and grabbing on to surrounding brush) can't solve. On a Sunday I saw lots of people of varying fitness levels at the summit, so this is a doable hike as long as you do it at a pace that's right for you. In terms of water, for me 5 liters was perfect.

7 months ago

Definitely a nice little ass kicker, although not as tough as I was expecting. We started at 2am and made it to the summit in 5 hours. Think it helped getting most of it out of the way in the dark... Lots of false summits toward the end and not being able to see what lies ahead helped ease the mental aspect. Very exposed so definitely start early to avoid the sun. I think next time will start an hour earlier to do the whole thing before the sun comes up. Brought micro-spikes and it saved us on the way down - provided lots of traction on those rocky slippery sections and we didn't have to slide on our butts like some people talk about. Trekking poles are a must as everyone else stated. 6-7 liters of water seemed to be the perfect amount. Lots of bugs on this trail so cover up and bug spray is a must!

8 months ago

Holy crap this trail is STEEP and LOOSE and RELENTLESS. The hardest hike I've done in SoCal so far. Bring trekking poles and a willingness to suffer.

8 months ago

As hard as you’ve heard and then some. The hike up to the summit is not even that bad. I’d say it’s the descent that takes its toll on you physically and psychologically. We started around 4:30am and finished close to 6pm. You ascend wildflower lined ridge trails and then up to false summits of pine. Gorgeous views and trail. But that descent is a beast. Trekking poles are a must! Although there was a guy trail running this beast with only 2L of water and he started after us and finished long before we did. So there are those with magical tendons, otherwise, help your knees and bring your poles. The trail is almost all exposed so if you’re doing this in the summer start in the dark and bring plenty of water. At least 6L worth.

8 months ago

All previous reviews are pretty good, read each one. I will just highlight some things that were not too obvious too me when I read them but realized on the trail. Trail (top 2.5 miles) is hard because the terrain, TRUE. But is not only the angle is the combination of angle and slippery. This trail has a high potential to injuries (coming down)!! I will NOT recommend this for the people thinking to do this as a training for Mt.Whitney or Cactus2Clouds. I done both and I think this hike is harder. Specially if you are training for something that you need a permit (e.g. Whitney), you don't want to miss/waste that permit due to an injury. There are plenty of hikes in the same area that have similar views and elevation, with a much lower risk to an injury. (Exception will be if training to do C2C2C or how to slide down).

Not trail terrain related: How come there is so many mosquito here? Because I went the first weekend of summer, I knew it was going to be hot. After reading how people ran out of liquid, I over packed a lot of water and electrolytes. That just backfired at me! Hiking this during the heat and with lot weight is even less fun. (I consume close to 5L of water and close to 1.5L gatorade). If you really want to try this hike with the best chances to finish it or with the less amount suffering, then try during the fall (I missed the previous review).

Oh almost forgot, thanks to rangers, Sierra club and anyone who maintains this trail and killed and trim some of the yuccas. If you hike this and get poke/cut from the yucca, please take that leave and bend the tip and poke back the plant keeping the tip away. Thanks!

8 months ago

Okay folks, this hike is often considered the most challenging trek in all of Southern California and I 100% believe it... my body is still aching all over from it. This is the BEAST of the San Gabriel mountain range. If you are to attempt this 14 mile, 12 hour+ grueling journey you MUST have the following: hiking poles, hiking boots for sure, at least 6/7L of water, try to avoid doing this in the heat or in the summer, and start this trail at 5am or 6am at the latest. I would say this hike is probably 3x more difficult than Mount Baldy. This hike will push your physical and mental limits to the edge. Another thing that makes this hike even crazier is just how steep you have to ascend and descent at different sections, it was literally a never ending rollercoaster ride. I highly recommend wearing long pants and a long sleeve tshirt as you will be dodging enormous yucca plants and overgrown brush all along the trail. It is inevitable that you will get stabbed and fall a few times. This mountain takes no prisoners.

I attempted to summit Iron Mountain on Cinco De Mayo (I guess because I'm crazy lol) and managed to only finish 3/4 of the trail which was brutal in itself (13.1 miles, 10.5 hours). My hiking partner and I only had a few hours of sleep the night before and we started at 9am so we definitely did not set ourselves up realistically for success. Also it was surprisingly warmer than we expected which definitely contributed to exhausting us even more than normal.


This is the same trailhead as Bridge to Nowhere. When you go down the fire road look out for the Heaton Flats sign on your right and the narrow green pathway will set you on your Big Iron journey. Bring an Adventure Pass to place on your car's dashboard and also grab a self issued day permit and keep a copy with you (this can be found at the trailhead).

UPDATE (6/9/18): I officially slayed the beast! Reaching this summit was one of the most exhilarating and intense things I have ever done physically and mentally. The view is breathtaking as you are in the heart of the San Gabriel mountains with 360 degree panoramic views of all the nearby mountain peaks such as Mount Baldy. There is a registry at the top that you can sign and leave your mark which I highly recommend since it's highly unlikely you will want to do this hike ever again or in the near future. It was a pure testament of willpower to reach the top (it felt like eternity to summit). This mountain is NO JOKE and any hiker that plans to attempt this peak must be super prepared. Also the mosquitoes and bugs when you start the last 2.5 miles to the summit start to get real intense. Definitely bring headlamps because you might be hiking in the dark back down the mountain. Another thing, this is the most isolated trail in the San Gabriels so you might be the only hikers the entire day along with just a few others, another reason to be fully prepared because you most likely will not run into any friendly hikers that can help you in case you need anything.

- @justroc @just.trek

9 months ago

There is nothing fun about this hike. The terrain is strenuous, exposed, tons of yucca plants, very steep, very rocky, and DEFINITELY need trekking poles. It's just as challenging coming down as going up. I have gotten 1/2 mile from the peak twice now and failed to summit due to it being cold and just too exhausting. Do not do this hike unless you are specifically trying summit Iron Mountain. This is not an enjoyable/challenging day hike, but rather a testament of will to prove you can get to the top.

9 months ago

Completed Iron Mountain 5/19 as part of the San Antonio Ridge Traverse. We started at 5:26AM and hit the summit at 10AM. In total, I brought 3 liters of water, 2 liters of electrolytes and a liter of coconut water. This trail is STEEP as most have said. Unless you are at peak fitness, bring trekking poles. Also bring sunscreen as much of this trail is rather exposed. While I did wear pants, I didn't feel they were necessary up Iron. Most of the Yuccas are cut back so as not to jab you. Just be careful where you're stepping and you should be fine. Having done C2C before, I felt this trail was more difficult than Skyline but YMMW.

9 months ago

3 of us Left at 5am with 8 liters of water a piece. Made the summit in 5 hrs, 49min. This was a beast of a hike... gives new meaning to steep. Going down is treacherous- bring trekking poles and start early - gets really hot and is mostly exposed with no shade

10 months ago

5 stars for difficulty.

Summited yesterday (4/29/18). Started hiking at 6:30am and got back to my car at 3:30pm. Took about 5 hours to reach the summit. This hike is incredibly difficult, very steep, with loose dirt and soil. I would consider trekking pole(s) mandatory.

Watch out for the poison oak in the first two miles, and the poodle dog bush throughout the entire hike.

11 months ago

Hiked up April 1, 2018 (Easter Sunday) with my little cattle dog, Vedder. Had hiked Rattlesnake a week prior and slammed Iron into my head all week long as a mental preparation.
This hike is no joke. For being 26, in “average” shape, this trail really put it into perspective for me. Towards the top I would take ten steps and break for 15 seconds. Once you turn that rock at the top to see the lonely summit pole, it all hits you though. Tears of joy.
Started at 5 am by headlamp and was back to the car at 4 pm. Be sure to dunk you’re entire head and face in the east fork San Gabriel river after exiting the Heaton Flat Trail on the way back. My god that felt so good. Good luck!

Sunday, January 28, 2018

Before doing this hike, get mentally prepared for the challenge! This hike shares the parking lot with "The Bridge to Nowhere" folks. Hike/walk past the yellow gate for 10-15 minutes until you see the bathrooms on the right. The trailhead reads "Heaton Flats Trail" and is located just past the bathrooms. Like many other reviewers mention - Bring AT LEAST 2 gallons/ 7-8 liters of water, wear long pants, and hiking poles. After the first 3 miles or so, there are MANY hills with several ups and downs and the Yuccas are unforgiving throughout the entire hike! I drank more water on the descent than on the ascent. I've never had knee problems but both of my knees took a beating (And I used hiking poles)!

For me, this is a love/hate hike. I loved it while on the ascent but hated the descent. It was definitely worth it once on the summit with the 360 degree views.

Wednesday, January 24, 2018

I wasn’t able to complete this hike because I didn’t have enough food and daylight to complete it, but this hike is a straight up relentless beast. It seems easy at first, but it gets mentally challenging as you go. This hike will get you questioning if you should turn back or not. The last mile is 2,000 feet of elevation gain. I can’t stress enough how crucial hiking sticks are for this trail. You will need them for the steep incline, and on the way down. Also, the trail can get narrow at times with lots of yucca plants. Wear long pants! The trail blazers of this trail really tried to mess with us hikers. Instead of going around the hills, the trail goes straight up over the hills only to go right back down which kills your determination even more. I will be doing this hike again to complete it, only next time I may bring overnight gear.

Thursday, January 18, 2018

TLDR: Very intense hike. And not just due to the elevation gain. The chaparral will try to scratch, scrape or otherwise impale you from every angle. Excellent training for other steep hikes.

Nice paved parking area with chemical restrooms. Huge flat dirt path from the parking area to the trail head. You could walk path to get the blood flowing while cameling up on some water then stretch out at the trailhead.

The trail from the trailhead to Allison Saddle is very reasonable. It is wide and not technical. It is moderately steep, but not worse than any of the prerequisite hikes for this one like Mt Baldy via Ski Hut and/or Old Baldy Trail, San Gorgonio via Vivian Creek, Three T's or San Jacinto. After about the 2 mile mark, the view opens up providing some great motivation to press to the summit.

All the above changes once you reach Allison Saddle. The trail narrows and you'll get very acquainted with the chaparral. It's not overgrown and no bushwhacking is required, but you may get stabbed more than once. Also the trail steepens significantly while footing gets quite loose in spots. Think along the lines of the first mile of Vivian Creek or that one section of Ski Hut Trail we all love so much. It's like that all the way to the summit. 35 degree plus incline in some sections.

I found the summit to be quite rewarding. You will be able to see most of the notable peaks in the area. If you're lucky like I was, you'll see snow on West Baldy. It's quite picturesque. Not only is the view excellent, but the feeling of tackling Big Iron is pretty great in and of itself. I actually relaxed up there for an hour eating, taking pictures and relaxing for what I knew was to come.

The descent back down was worse than the climb. It's downright slippery all the way back to the saddle. If I had left my trekking poles at home I would have been cussing at myself the whole time. This was the only hike I have done recently that I actually took a break coming DOWN the mountain. Once at the saddle, its a roller coaster hike back to the car. After the previous section, I found it quite relaxing.

All in all this was an excellent hike. But I went there for training for C2C and Whitney. Had I went there for just a fun day hike like say San Gorgonio, I would have been slightly disappointed. This wasn't fun. BUT it was rewarding and I am proud to say I tackled Big Iron once and for all. Now on to bigger and better things. I may revisit Big Iron a week out from C2C, but probably not before that. I'll stick to Old Baldy Trail and just hike it faster and/or with more weight.

Thursday, December 28, 2017

Walked from the parking lot down the dirt road to the Heaton Flats Trail head and took the trail all the way to Iron Mountain. To give a good perspective on it's difficulty, I'm a 20 year old 6'1" 180lb male who plays rugby and works out 2-3 times a week. I hike/backpack probably 5-6 times a year and I barely was able to complete this trail and my legs were cramping severely a mile before the summit. My brother is a 22 year old 6'2" 205 lb male who is similarly physically active but has had a couple more years of drinking, so he's not in as good of shape. He gave it all he had but stopped about 1 mile past Allison's saddle after getting nauseous and his muscles cramping. That being said, the views were awesome and I would do it again if I can get into better shape first. So, if you enjoy pain or are in a lot better shape than me, give Iron a run for her money. Also, the hike took us a full 9 hours (probably would've been a little faster without my brother but who knows).

Thursday, December 21, 2017

the c2c is way easier then iron mountain and I do up to 22 mile hikes but this hike was very difficult and I ran out of water I had a little less than a mile to go I was at 12.35 but do to the time and the early nights we had to turn around cause it just as difficult going down as up, this is the first time I've ever ran out of water. Do the C2C to prepare for this hike. You can be the best hiker but there is a trail out there that will kick your butt!!

Friday, December 01, 2017

This is a five star trail mainly because I like climbing steep hills and this mountain met that expectation. If you don't like hiking up steep hills then this hike is NOT for you. The view was as good as any other mountains in this area. A friend and I did this fun hike today. We completed it in 5 hours 30 minutes. It exceeded my expectations. A solid and fit hiker should expect to complete this trail in 7-10 hours.

Monday, November 06, 2017

In preparation for C2C, my group and I conquered Iron Mountain. This was my second time on the Heaton Flat Trail. I hiked solo up to the Alison Mine Saddle last year in preparation to do the entire hike with two other hikers. Unfortunately, it never happened.

So, on Saturday, Nov 4th six hikers and I set out to conquer this beast. I can honestly say the Iron Mountain certainly lived up to its billing as being the toughest hike in the San Gabriel Mountains. The final two plus miles to the peak were steep and relentless. I had no doubt we would make it, but I seems like the last two miles just went on forever!

For our efforts, we were rewarded with some of the most awesome views of all the surrounding ranges and peaks. We had perfect weather and very little wind at the peak. It was probably in the 40's at the top and never got higher than 60 throughout the hike.

We each carried between 4 to 6 liters of water plus a liter or so of electrolytes or coconut water. We have C2C in two weeks. It will be my second summit from the Skyline trail and my groups first time. It will also be my 8th summit of San Jacinto (from various trailheads).

Iron Mountain - I've got your number now! See you again next year as my Hike Beyond the Hills friends and I conquer you again. ;)

Monday, October 30, 2017

Good hiking, panoramic views, slows you down on your descent due to loose rocks

Sunday, October 22, 2017

Just completed Cactus to Clouds on 10-14, my first time. Had never done Iron Mountain so I figured, why not while I was on a roll. Started at 7:15 am, and it was a chilly 50 degrees. Didn't take long to get warmed up. The first 4 miles are moderately difficult with lots of beautiful, distracting scenery. I snapped over 100 pictures during this hike.

I brought 3.5 liters of water and no other food or drink. When I reached the saddle point before the 2.5 mile ascent, I stored 1.5 liters of water in the shade to minimize the weight I would have to carry up the steep grade. I made the mistake of carrying too much water on the Skyline Trail portion of C2C the prior week, and the weight made the ascent up the last 2 miles to Grubbs Notch pure hell.

The last 2.5 miles of Iron Mountain exceed the difficulty of the last 2.5 miles of C2C in terms of steepness. However, C2C you have to travel 8 miles up steeper terrain before you reach that last 2.5 mile segment up to Grubbs Notch so you begin that ascent far more tired than this one.

Nevertheless, this was a beast. Many times when I had to use all fours to climb up the loose dirt and gravel up grades of 70 degrees. Fortunately, as you ascend higher, the temperature drops. It took 4 hours 45 minutes to reach the summit, and it was about 60 degrees at the top. The pace was leisurely enough that I did not feel as drained as I did at Grubbs Notch the week before.

Mt. Baldy seems close enough that you want to just keep hiking to notch another summit for the day and avoid having to descend those dreaded steep trail sections you just came up. The views are spectacular from the summit, and I rested for 20 minutes soaking up the scenery before heading down.

You have to be very, very careful on the descent. Practice landing on the balls of your feet instead of your heel, and you will avoid those nasty wipeouts where you slide forward and land hard on your butt.

Many portions of this trail are very narrow because brush branches are growing over the trail. Lots of prickly yucca plants and other scratchy plants were a nuisance since I was wearing shorts and short-sleeves. Long sleeves and long pants would minimize this problem.

By the time I reached my stored water, I had gone through my 2 liters so I poured the remaining 1.5 liters into my camelback and headed back. Total time was 9 1/2 hours. Wished I had done this before C2C. It would have been better preparation than the Bear Canyon Trail up to Baldy.

I will be doing it again soon.

Saturday, October 07, 2017

Finally got out to do this one. A beast it sure is. They don't call it big bad iron for nothing. Be ready for this one. I also got 14.6 miles round trip from the parking lot.

Tuesday, September 12, 2017

A pleasant stroll alongside friendly Yucca plants.

If you're seeking yourself and the answer to life, the universe, and everything, Big Iron is calling for you. The scenery is beautiful and full of surprises. This hike is like a roller-coaster.

This was my first solo hike. I wouldn't recommend ever doing this solo unless you're crazy like me. The solitude was priceless yet unfamiliar. I didn't see a single person all day long, but I did see a lot of poop and birds like quail running across the trail. I started and ended in darkness 6AM-8PM. The forecast called for a sunny day, but I was embraced by an epic thunderstorm 4 miles in. I stood still in awe as lightning waltzed around me. The temperature dropped precipitously then I showered for 30 minutes. It turned out to be a beautiful morning with rainbows and sunbeams streaming through the clouds. The real fun began as I started ascending Big Iron itself. The wind pushed me around and tested my balance during the final mile. It was a neat day in nature.

Saturday, August 26, 2017

This unfortunately is one of my least favorite hikes. I want to like it, but can't! The views aren't great, the yucca is ouchy and you'll be sure to slide a good portion of the way down while holding onto shrubs for dear life. We do not carry hiking poles but I don't know if that would have made a major difference. We also did it in the peak of summer heat and this one has no shade so that might have colored our feelings about this. Start very early. You'll be surprised how long this one takes.

Tuesday, August 15, 2017

Brutal. Love it! Good prep for C2C or Whitney. If you can conquer this in 6 hours or less then you can easily do Whitney. Last three miles of the climb are pure amazing pain. Bring 6-7 liters of water and store the water just before the climb. Take 3 liters for the final climb. Don't underestimate the climb. Remember, you have to go down what you climb.

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