Starting from the spacious Pine Creek Trailhead outside Pine Valley, the Secret Canyon Trail weaves and bobs its way along the canyon of Pine Valley Creek, finally emerging some 15 miles later at Horsethief Canyon, near Barrett Lake. Just 2 miles down this trail, you can experience an ant's eye view of the surrealistically lofty Pine Valley bridge, built in the mid-1970s over the deep gorge of Pine Valley Creek.
From a point on Old Highway 80, west of Pine Valley and partway up the grade toward Guatay (precisely at mile-marker 3.5), turn south onto the narrow trailhead-access road. Drive for about a minute to its end. Note that the trailhead and the trail are in Cleveland National Forest, so you will need to display a National Forest Adventure Pass on your car for the privilege of parking (call 619-445-8341 for more information).
Pick up the trail at the far end of the trailhead parking lot and descend to Pine Valley Creek, where you cross ankle-deep water to reach the oak-lined east bank. Here and farther downstream, the white blossoms of yerba mansa and fluorescent-pink blooms of wild rose should put on a good show for the next couple of months. Due to the late rains, the chaparral on the slopes above should bloom best later this month, with blue- and white-blossoming ceanothus highlighting the variegated display.
After almost two miles on the east bank, you pass directly under Interstate 8's Pine Valley Bridge. Supported by four massive pillars, this is the tallest bridge (400+ feet) on the interstate highway system. Past the bridge, the trail enters the Pine Creek Wilderness, a remote, roadless area of the Cleveland National Forest more popular of late with illegal immigrants sneaking northward than recreational hikers.
Small, rock-bound pools can be found in the bed of the stream in the mile or so beyond the bridge -- good for soaking your feet, at least.