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.
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).
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).
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).
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.
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.
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.
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.
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.
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.