Catch the best autumn scenery on the one-way Kelly Ditch Trail across the Cuyamaca Mountains.

The 5.5-mile Kelly Ditch Trail, completed in 1985, is perhaps the most beautiful pathway yet built in the Cuyamaca-Julian area. This hiking/horse trail is routed partly along a century-old diversion ditch. You'll also tread over dim traces of "skid roads" where freshly cut logs were slid down off the mountain ridges to serve as lumber and fuel for the mines and boom towns of Julian's late-1800s gold-rush period.

With the logging era long gone, a second-generation forest of oaks and conifers coats the hills now. This is a perfect place to explore in late October, when the days are cool and the color of autumn leaves warmest in hue. Black oaks exhibit full crowns of crispy, golden leaves, and fat, glossy acorns litter the ground. Crimson Indian-basket bush and poison oak leaves show their stuff amid the glades of russet-colored bracken fern.

The Kelly Ditch Trail is best hiked one-way, with the aid of a car shuttle or a drop-off-and-pick-up arrangement. The easier (mostly downhill) direction is south to north: Cuyamaca Reservoir to William Heise County Park. The starting point is on Highway 79, 8.3 miles south of Julian, near the intersection of Engineers Road and Highway 79. The trail ends at a parking lot just inside William Heise County Park. Heise Park can be reached by turning south from Highway 78 on Pine Hills Road, west of Julian, and following directional signs to the park.

Start your hike just north of where Highway 79 crosses the Cuyamaca Reservoir dam. In the first mile you'll travel along the remnant Kelly Ditch, constructed by pick-and-shovel labor more than a century ago. Its purpose was to divert runoff from the south slope of North Peak into the then-new reservoir.

After a mile the trail climbs abruptly out of the ditch, veers north through a sun-struck patch of chaparral, and then crosses paved Engineers Road. You pass a spring-fed horse trough and continue a short distance to join a disused dirt road. Turn right and follow the road's gentle uphill course around the west slope of North Peak. You'll stroll past a couple of ancient sugar pines and enter a delightful, parklike meadow, dotted with black oaks and carpeted by bracken ferns. On the clearest days, blue sky meets the blue Pacific horizon more than a hundred miles to the west.

At the next fork (about 2.5 miles from the start), you're directed left across a sunny bowl and then up to a low ridge shaded by live oaks, black oaks, Coulter pines, incense-cedars, and white firs. From this point, the highest elevation of the hike, a long series of switchbacks leads you steadily downward (and north) to a small stream -- a fork of Cedar Creek -- fringed with ferns and wild berries.

On past the creek, the trail goes up a steep ravine evidently cut deeply by some agent other than running water. This is the remnant of one of the skid roads. After a 130-foot gain, the trail tops a saddle and joins a dirt road. You descend to a second creek (the main fork of Cedar Creek), cross a meadow beyond, and pick up the last link of trail leading to the Heise Park entrance.