If you’ve driven on Interstate 8 east as far as Pine Valley you’ve almost certainly taken notice while driving over the high-altitude Pine Valley Creek Bridge just before the Pine Valley exit. Formally known as the Nello Irwin Greer Memorial Bridge it is considered one of the highest bridges in the U.S. (450 feet high).
Looking to get some photos of the bridge we learned that the Secret Canyon Trail goes beneath it. We found the trailhead by getting on Old Hwy 80 in Pine Valley and driving a few miles west to Pine Valley-Las Bancas Road where there’s a big Cleveland National Forest sign announcing the “Pine Creek Trailhead” on the south side of the road.
It’s a short drive south to the end of the road where there’s ample parking and restrooms. A US Forest Service Adventure Pass must be displayed in the windshield in order to park here. A sign marks the beginning of the trail just south of the restrooms.
The trail starts on the west side of the canyon and quickly drops to make a crossing at Pine Creek. If it has rained recently you may not feel like trying to cross, but when we went it was about 3 weeks since the last significant rain and there was just a moderate flow. It’s usually pretty easy to cross as long as the water isn’t running too deep. We’ve hiked the trail a number of times over the years and only once did we have to turn back because of unexpected high water.
The trail continues south above the east bank, sometimes gaining elevation in the canyon above the creek, sometimes descending to creek level. It’s an attractive and pleasant trail with oak and willow trees, manzanita groves, and numerous other plants. It’s approximately 2 miles (one-way) to the bridge and I’d classify the trail as moderately difficult because of the elevation gain and loss which is about 600 feet according to various trail guides. You can always take it more slowly to make it easier, it’s not that far.
Here are the photos (click images for an enlargement to open in a separate browser tab).

This was the same crossing on another day when a decision was required about getting wet up to the knees!

We hiked another 1/4 mile further south beyond the bridge so we could get this clear view of the whole thing (looking north).
As you can see from that last picture, once you cross south of the bridge the trees pretty much disappear and the trail gets hot and dry so unless you’ve planned a much longer hike it’s a good place to turn around.