Skyline to Santiago Peak

This 39.2-mile out-and-back route begins at Skyline Drive Trailhead in Corona and climbs to Santiago Peak, the highest point in the Santa Ana Mountains. The route follows a mix of fire roads and rugged singletrack, climbing steadily along ridges with expansive views of the Inland Empire, Orange County, and the Pacific Ocean. The return route descends via 3S04 and the steep Skinsuit Trail, creating a challenging but rewarding high-mileage adventure for strong hikers, trail runners, or fastpackers.

From the Skyline Drive Trailhead, the route begins with a long, steady climb along Skyline Drive, a wide fire road that gains elevation with sweeping views toward Mount Baldy, the San Gabriels, and the coastal plain. This is a sun-exposed ascent, so early starts are best.

Continue climbing until Skyline Drive connects with Main Divide Road. The route follows this ridge-line road all the way to Santiago Peak, the high point of the Santa Ana Mountains. The summit is topped with communication towers, but the views are far-reaching, on a clear day, you can see the Pacific Ocean, San Bernardino Mountains, and even Catalina Island.

After taking in the views, return along 3S04, which rolls along the ridge before turning toward the Skinsuit Trail junction. Skinsuit descends steeply through rugged, exposed terrain with loose sections that require careful footing. The trail delivers you back near Skyline Drive, closing the route with a direct downhill finish.

Flora & Fauna

• Flora: Chaparral, sage scrub, manzanita, and oak groves at lower elevations. Spring brings a burst of wildflowers like lupine, poppies, and bush sunflowers.

• Fauna: Deer, coyotes, hawks, lizards, and the occasional rattlesnake in warmer months.

Permits

• No wilderness permit required.

• Adventure Pass or equivalent is required for parking at Skyline Drive.

Camping

• This route is most often done as a long day hike or trail run.

• Dispersed camping is allowed in Cleveland National Forest with a valid California Campfire Permit, though water sources are scarce.

Best Season

• Spring and fall offer the best combination of moderate temperatures and clear skies.

• Summer can be dangerously hot with little shade—start early and carry plenty of water.

• Winter may bring cool temperatures, mud, or limited visibility at the summit.

Need to Know

• This long distance route is great training for ultra marathon runners. 

• There is no reliable water along the route—carry all you need.

• Skinsuit Trail is steep, exposed, and loose in sections. Trekking poles and sturdy footwear are recommended.

• Sun protection is essential—shade is minimal.