Mt Wilson Hiking Guide
Mt Wilson stands as one of the most rewarding summit hikes in the greater Los Angeles area, rising to roughly 5,710 feet above sea level and offering sweeping views of the LA Basin, San Gabriel Valley, and on clear days, the Pacific Ocean. The classic route from Chantry Flat gains approximately 4,500 feet over a round-trip distance of about 14 miles, making it a genuine full-day commitment for most hikers. The trail passes through first-growth bigcone Douglas-fir forest, seasonal streams, and historic infrastructure including the Mt Wilson Observatory complex near the summit.
Trail Overview and Route Options.
The most popular approach to Mt Wilson begins at the Chantry Flat trailhead in Arcadia, following the Sturtevant Trail through Big Santa Anita Canyon before climbing steadily toward the summit ridge. This route is approximately 14 miles round-trip with around 4,500 feet of cumulative elevation gain. A shorter but steeper alternative departs from Red Box on Angeles Crest Highway, cutting the round-trip to roughly 7 to 8 miles. Both options converge on the upper trail near Manzanita Ridge. The Chantry Flat approach is more scenic and forested; the Red Box route suits hikers looking to summit efficiently without a pre-dawn start.
Elevation Profile and Physical Demands.
The Chantry Flat route starts at approximately 1,600 feet elevation and climbs to the Mt Wilson summit plateau near 5,710 feet. Much of the gain is concentrated in the middle section of the trail as it exits the canyon and ascends the open ridge. Expect sustained switchbacks with limited shade above the canyon floor. The Red Box route starts around 4,400 feet, making it the more accessible choice for hikers who want a real workout without a 7-plus-hour commitment. Either way, trekking poles help significantly on the descent, where loose decomposed granite can make footing unpredictable.
What to See at the Summit
The summit area of Mt Wilson is unusually developed for a Southern California peak, hosting the Mt Wilson Observatory, several telecommunications towers, and a small visitor area with picnic tables and restrooms. The observatory has operated since 1904 and played a central role in Edwin Hubble's discovery of other galaxies. On clear days the view spans from the Pacific Ocean to the west to the San Bernardino Mountains to the east. The Summit Meadow area just below the antenna farm offers quieter rest spots away from the parking lot used by drive-up visitors who access the summit via Mt Wilson Road.
Seasonal Conditions and Weather.
Spring offers the most pleasant hiking conditions, with cooler temperatures, seasonal waterfalls in Big Santa Anita Canyon, and wildflower blooms along the lower trail. Fall brings crisp air and exceptional visibility, often yielding the clearest summit panoramas of the year. Winter hikes are possible and strikingly beautiful when snow dusts the upper ridge, but ice on the trail above 4,000 feet can require microspikes. Summer is the least recommended season due to temperatures that can climb above 90°F in the canyon, afternoon thunderstorm risk in July and August, and limited shade on the upper ridge. Always check current fire and road closures through the Angeles National Forest website before heading out.
Trailhead Access and Parking
The Chantry Flat trailhead is located off Santa Anita Avenue in Arcadia and is accessed via a winding narrow road. The parking lot fills quickly on weekend mornings, often by 7:30 a.m. in spring and fall. An Adventure Pass or Interagency Annual Pass is required to park at Chantry Flat. The lot can accommodate roughly 80 vehicles, but overflow parking along Santa Anita Avenue adds capacity. Arriving by 6:30 a.m. on weekends is strongly advisable. The Red Box trailhead sits directly on Angeles Crest Highway (CA-2) and offers more reliable parking, though the highway itself may close during winter storms or fire weather events.
Safety Considerations
Mt Wilson via Chantry Flat is a serious all-day hike that has caught many underprepared hikers off guard. Bring a minimum of 3 liters of water per person; there is no reliable water source on the upper trail and the creek crossings in the lower canyon should not be counted on for potability without filtration. Cell service is spotty through most of the canyon. Inform someone of your itinerary and expected return time before departing. The trail is well-marked but junctions near the summit plateau can confuse first-time visitors. Starting before 7 a.m. gives ample buffer to complete the Chantry Flat route before temperatures peak and afternoon light fades on the descent.
Hiking tips for Mt Wilson
- Start the Chantry Flat route no later than 6:30 a.m. on weekends to secure parking and finish the 14-mile round-trip well before dark.
- Carry at least 3 liters of water per person from the trailhead; the lower canyon streams require filtration and the upper trail is completely dry.
- Pack microspikes between November and March — the ridge above 4,500 feet can hold ice well after winter storms even when the lower trail looks clear.
- An Adventure Pass or Interagency Annual Pass is required to park at Chantry Flat; rangers actively enforce this, especially on weekends.
- Download an offline map before leaving cell range — service drops out through most of Big Santa Anita Canyon and does not reliably return until the summit plateau.
Nearby trails to explore
- Sturtevant Falls Trail
- Monrovia Canyon Falls Trail
- Eaton Canyon Falls Trail
Hike this trail with TrailMates
Tackling Mt Wilson is far more rewarding with the right group behind you. Use TrailMates to find hiking partners matched to your pace and skill level, so you can take on this strenuous summit with confidence and safety built in from the start.