Shadow Canyon
Shadow Canyon is a steep, strenuous Open Space trail that climbs through boulders to the saddle between South Boulder Peak and Bear Peak, the standard route to both of Boulder's southern summits, approached from the South Mesa Trailhead.
Outdoor Boulder › Destinations › Shadow Canyon
Shadow Canyon quick facts
- Distance
- A long out-and-back day. OSMP does not publish an official round-trip mileage for the Shadow Canyon route to the peaks, so plan for a full day out and check the trail map before you go.
- Elevation gain
- Substantial and steady. The route climbs to the saddle and on to South Boulder Peak, Boulder's highest summit at 8,549 feet. OSMP does not publish a trailhead-to-summit gain figure.
- Difficulty
- Strenuous. A steep, rocky climb that stair-steps through boulders with loose footing, and the summits themselves require some scrambling.
- Trailhead
- South Mesa Trailhead, reached by linking the Mesa Trail with the Shadow Canyon spur (Towhee and Homestead are common lower connectors).
- Parking
- Paid lot on the north side of Eldorado Springs Drive (Highway 170), with 48 standard spaces and 3 ADA spaces. It fills early on weekends; parking on Highway 170 is not allowed.
- Dogs
- Allowed. Dogs must be on a hand-held leash unless they meet the Voice and Sight control standard and display a City of Boulder Voice and Sight tag.
- Best season
- Late spring through fall for the summits. Start at dawn in summer to be off the high ground before afternoon storms; snow and ice make the upper canyon treacherous in winter.
Shadow Canyon at a glance
Shadow Canyon is the steep, rugged staircase up the back of Boulder's southern skyline. The trail leads through a steep incline to the saddle between Bear Peak and South Boulder Peak, weaving in and out of boulders as it climbs from conifer forest into a large burn zone, with unique views of Devil's Thumb along the way. It's the standard route to both summits, and it earns its reputation: this is a strenuous, full-day effort, not a stroll.
The route to the peaks
Almost everyone starts at the South Mesa Trailhead and links the Mesa Trail to the Shadow Canyon spur, then grinds up the canyon to the saddle. From that saddle, South Boulder Peak sits in one direction and Bear Peak in the other, which is why so many hikers tag both in a single loop or out-and-back. South Boulder Peak is Boulder's highest summit at 8,549 feet, rocky enough on top that reaching the true high point takes a little scrambling. OSMP doesn't publish an official round-trip mileage for this route, so plan for a long day and carry the map.
How steep and rocky it really is
Be honest with yourself about the terrain. The upper canyon is a relentless stair-step over and around boulders, with loose rock that can shift underfoot and roll toward hikers below, so keep your spacing and watch your footing. Trekking poles help, sturdy shoes help more, and the descent is often harder on knees and ankles than the climb. If loose, steep, technical trail isn't your idea of a good time, this is not the peak to start on.
Start early, watch the sky
This is an exposed, high route, and Colorado afternoons build thunderstorms fast in summer. Start at or before dawn so you can be off the saddle and the summits before storms develop, often by around midday. There is no safe place to be in lightning up there. If clouds are stacking up, turn around early; the peaks will still be there next time. See our thunderstorm safety guide for how to read the timing and what to do if a storm catches you out.
Trailhead, parking, and hours
The South Mesa Trailhead is 1.7 miles west of Highway 93 on Eldorado Springs Drive (Highway 170). Parking is a paid lot on the north side of the road, with 48 standard spaces and 3 ADA spaces, and it fills quickly on weekends, so show up early. Parking on Highway 170 is not allowed, and vehicles left in the roadway can be ticketed or towed. The trailhead is open 5 a.m. to 11 p.m. daily and has a restroom and picnic tables (grills and stoves are prohibited).
Dogs, wildlife, and sharing the trail
Dogs are welcome in the South Mesa area, but they must be on a hand-held leash unless they meet the Voice and Sight control standard and display a current City of Boulder Voice and Sight tag. Cleaning up after your dog is required by law. This is real wildlife country: black bears and mountain lions live here, along with raptors, mule deer, and coyotes, so keep dogs close and give wildlife space. Note that no bicycles are allowed in this area; the mountain biking trails are across Highway 170 in the Doudy Draw area.
Best season and time to go
Late spring through fall is prime time for the summits. In summer, the move is an early, pre-dawn start to beat both the crowds at the small lot and the afternoon storms up high. In winter and early spring the upper canyon holds snow and ice and can be genuinely treacherous; traction devices and honest judgment matter, and turning back is always the right call when conditions are bad.
Nearby trails and guides
- South Boulder Peak: Boulder's highest summit at 8,549 feet, reached by way of Shadow Canyon.
- Bear Peak: the other summit off the same saddle, often paired with South Boulder Peak.
- Thunderstorm safety: how to time an exposed peak day and what to do when a storm builds.
- All hikes in Boulder: the full hiking hub, sorted by difficulty.
Recommended nearby
A few local spots we'd point a big peak day toward.
[CLIENT SLOT: featured gear shop near South Mesa]
[One honest line: traction, layers, or trekking poles for a big peak day.]
[CLIENT SLOT: featured cafe near Eldorado Springs]
[One honest line: an early coffee or a post-hike bite south of town.]
[CLIENT SLOT: featured guide or shuttle service]
[One honest line: a local who knows the peaks if you'd rather go with someone.]
Shadow Canyon FAQ
How hard is the Shadow Canyon trail?
It's strenuous, one of the steepest sustained climbs in Boulder's Open Space. The trail leads through a steep incline to the saddle between Bear Peak and South Boulder Peak, stair-stepping in and out of boulders with loose rock underfoot. If you continue to either summit, the tops are rocky and require some scrambling. Treat it as a full day, not a casual walk.
How do you get to South Boulder Peak and Bear Peak from Shadow Canyon?
From the South Mesa Trailhead you link the Mesa Trail to the Shadow Canyon spur, then climb Shadow Canyon to the saddle between the two summits. From that saddle, South Boulder Peak (Boulder's highest at 8,549 feet) is a short, rocky push in one direction and Bear Peak is in the other, so many hikers tag both in a single long day.
What time should I start to avoid thunderstorms?
Start at or before dawn in summer. Colorado's high country builds afternoon thunderstorms, and the saddle and both summits are exposed, no place to be in lightning. The goal is to be off the high ground and heading down before storms build, often by around midday. Watch the sky, and turn around early if clouds are stacking up.
Are dogs allowed on the Shadow Canyon trail?
Yes. In the South Mesa area, dogs must be on a hand-held leash at all times unless they meet the Voice and Sight control standard and display a current City of Boulder Voice and Sight tag. Picking up after your dog is required by law, and there's a dog waste station at the trailhead. The steep, rocky terrain is hard on paws, so bring water and judge the day honestly.
Where do I park for Shadow Canyon, and is there a fee?
Park at the South Mesa Trailhead lot on the north side of Eldorado Springs Drive (Highway 170), 1.7 miles west of Highway 93. There's a parking fee, and the lot has 48 standard spaces plus 3 ADA spaces. It fills quickly on weekends, so arrive early. Parking on Highway 170 is not allowed and vehicles can be ticketed or towed.
Sources
Facts on this page are drawn from these authoritative sources: