Coal Canyon: an Orange County hiking treasure via the off-ramp to nowhere


Coal Canyon Waterfall via the Off-Ramp to Nowhere

Date Hiked: April 26, 2009
Best Season: Spring Winter
Check Trail Conditions: Coal Canyon Ecological Preserve (858) 467-4201
  • Distance: 6 miles round-trip
  • Elevation Gain: 680 feet
  • Route Type: Out-and-Back
  • Trail Type: Paved, dirt, creek, rocks
  • Difficulty: Moderate

One of the coolest Orange County hikes Jeff and I have done is the Coal Canyon hike located on the border of Riverside and Orange County — a 5.4 mile round-trip there-and-back hike nestled in a box canyon between Corona and Anaheim Hills.  Accessible from the Santa Ana River Trail (we recommend the Green River Road exit along the 91 Freeway in Corona), this  hike includes what used to jokingly be referred to as the “off-ramp to nowhere.” 

Now cut off from the freeway and fenced up, Coal Canyon Road used to be an actual freeway exit that simply looped visitors under and back on to the freeway.  In 2003, access was permanently closed when Coal Canyon was turned into a wildlife corridor connecting Chino Hills State Park and the Santa Ana Mountains.  The full stretch of trail falls under the jurisdiction of the Santa Ana River Trail, Chino Hills State Park, and  the Coal Canyon Ecological Reserve.

Jeff and I did this hike in April 2009, and we were fortunate to not see another single living person until about 2/3 of the way along the return leg of our hike — even then, it was just a couple mountain bikers.

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Wildflowers greeted us along the walk from Green River golf course to Coal Canyon -- a pleasant surprise alongside one of Southern California's busiest freeways.

Since the Coal Canyon exit is closed, the only way to access the trail head is from the section of the Santa Ana River Trail that parallels the 91 Freeway.  The nearest parking is at the dirt “lot” — crowded on weekends — that is really just a shoulder off the north side of Green River Road, located along the river trail bike path just east of the Green River Golf Club (exit at Green River Road).

From the dirt lot, it’s an easy paved 1-mile walk along the river and the edge of the gold course to the Chino Hills State Park entrance located at Coal Canyon (the bike path is now located behind the golf course, due to the Santa Ana river diversion project that moved the river in 2010).

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Looking south from the Santa Ana River (on the west side of the 91 freeway), at the former Coal Canyon off-ramp. This is now part of Chino Hills State Park.

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The former westbound Coal Canyon on-ramp to the 91 freeway. This has been turned into wildlife corridor, and is part of Chino Hills State Park.

Once at the former freeway underpass, head south underneath the 91 Freeway — be sure to check out the cameras that are set up to monitor wildlife crossings.  Coal Canyon Road (now dirt, instead of paved) leads you to a narrow dirt trail that used to be a service road (it’s marked with a Coal Canyon sign).

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Entering the Coal Canyon region, and trailhead, of Chino Hills State Park, located south of the 91 freeway.

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Hiking the first leg of the trail, an old service road.

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It is hard to believe this is just a 5 minute hike from one of the busiest freeways in southern California.

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Despite the warm dry April weather, we were still able to catch occasional glimpses of wildflowers along the Coal Canyon trail.

In just a short bit, the service trail intersects a creek wash, which was bone dry at the time of our hike.  We presumed that the trail actually used to run alongside the creek bed, but had been washed away, particularly since the trail again becomes visible along the east bank of the creek after a few minutes.  The trail exits Chino Hills State Park and crosses into the Coal Canyon Ecological Reserve — under the jurisdiction of the California Department of Fish and Game (where guns and hunting are allowed).

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Here the trail runs into a wash that we follow the rest of the way.

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Leaving Chino Hills State Park. Loaded firearms and hunting are permitted along this stretch.

Despite feeling like you’re really off the beaten bath at this point, it is still possible, when looking behind at the trail traveled, to see the 91 Freeway and the Yorba Linda housing sprawl.

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Looking north from the trail, to the 91 freeway and the Yorba Linda homes beyond.

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The rocky outcrops and vegetation get even more diverse the deeper we go into the canyon.

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Looking back (north) towards the 91 freeway and Yorba Linda. Now we're really feeling off the beaten path!

At about 2/3 of the way into the box canyon, the trail again succumbs to the dry creek wash, which is lined with tall oaks and flanked with heavy brush that climbs up both sides of the canyon.

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Big oaks like this one line the dry creek bed about halfway back into the canyon, providing much-needed shade and a great spot to stop for a picnic.

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Our first wildlife up close, a lizard.

Proceed along the creek bed as it narrows and the vegetation becomes thicker.  The dry creek bed and rocks here are heavily marked with white calcification from what we assumed were mineral salts left behind by the creek water drying up.

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Calcified rocks along the creek bed finally leads us to the first signs of water.

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Our path (the creek bed) gets much narrower.

As we neared the end fo the canyon, the creek bed became a bit muddy and temperatures dropped to a much cooler level.  The creek bed takes a sharp turn right and literally dead ends at a narrow canyon enclosed by high rock walls — and a tiny little trickling waterfall.

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A fabulous little tea spout-shaped limestone waterfall awaits us immediately after making a sharp right turn into the end of the box canyon.

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The base of the waterfall.

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Jeff climbs up the wall opposite the waterfall, to snap a photo of me. We're literally at the very end of the box canyon.

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Me underneath the tiny sparse waterfall -- it generated just enough spray to cool us down a bit after our hot hike out to the box canyon.

The canyon terminus is a great place to stop and rest a while while taking in the cool damp temperatures.  You truly feel fully isolated from civilization, despite being only a few miles from traffic and congestion.

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Jeff was positively stoked to discover a horny toad along the creek bed on the hike back out of the canyon.

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Some sort of spiny fruit. We've seen these in Chino Hills State Park and Santiago Oaks Regional Park. I think this year, I'm going to make a real effort to learn more about our local wild flora and fauna.

Re-trace your steps to return to the trailhead and the river trail.  Or, change things up a bit, like we did, by hiking the creek bed the entire way back to the Coal Canyon trailhead.

While this hike is suitable for older kids who are experienced hikers, we think that our teenage kids would still be a bit bored by the trail — although they’d think the waterfall at the end is cool.

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  1. says

    This was a very cool hike. The official trail guides call for you just to go up and back on the same trail, but we decided to walk all the way back down the dry creek bed instead for a very slightly different view.

    We’re hoping to go back soon when the falls are a bit fuller, and are curious to see whether the creek is more difficult to navigate at the top!

    • says

      It really was a pleasant surprise. We’ve both driven past the Coal Canyon off-ramp a couple hundred times, but never gave a second thought to the canyon until we came across some trail write-ups. So close to bumper-to-bumper traffic, yet a world away. I’m looking forward to hiking it again when the wildflowers are in bloom.

  2. Rev Vandervort says

    The spiny fruit is commonly known as Wild Cucumber. The Tuberous root of this plant can weigh up to 200 pounds!!! My guess is that the species you found is Marah Macrocarpus(Cucamonga Manroot).

    You might find it particularly interesting that this plant was first described by Edward Lee Greene.

    On a clear day, the views are amazing from the Main Divide Road that goes up to the right at the base of the canyon.

  3. says

    Is there Poison Oak along the trail? (A couple of miles farther downstream, during the 1940s, there was a lot of it in the hills along the south side of 91.) If so, hikers should be prepared to identify it and avoid skin contact.

  4. Kurt says

    That’s an incredible wildflower shot you captured. I’ve never seen that variety on any of my hikes. If anyone knows what that flower is called I’d be very interested in finding out.

  5. Louise B says

    We did this hike today. What a great way to escape the Orange County crowds. Once we left the bike trail, we didn’t see another soul. Thanks for the detailed write up.