Gregory Canyon
Gregory Canyon is a wooded trailhead and steep canyon trail at the base of Flagstaff Road in west Boulder, one of the main gateways to Green Mountain, Saddle Rock, and the Flatirons. Parking is paid, the lot is small, and dogs are welcome under Voice and Sight.
Outdoor Boulder › Destinations › Gregory Canyon
Gregory Canyon quick facts
- Distance
- A short, steep connector. OSMP describes the trail climbing west from the trailhead, over a ridge, up to a saddle, then down to a dirt road below Realization Point. OSMP doesn't publish an official mileage, and most people hike it as one leg of a longer loop to Green Mountain, Ranger, Saddle Rock, or Flagstaff.
- Elevation gain
- Steady and steep. The trail gains height quickly through the wooded canyon up to the saddle. OSMP doesn't publish an official elevation-gain figure for it.
- Difficulty
- Moderate to hard. It's short but steep and rocky in places, so it works your legs and lungs. OSMP doesn't assign formal difficulty ratings to its trails.
- Dogs
- Voice and Sight. Dogs may be off leash only if they meet OSMP's voice-and-sight control standard and wear a City of Boulder Voice and Sight tag; otherwise they must be on a hand-held leash. Cleaning up after your dog is required by law, and there's a dog station at the trailhead.
- Parking / fee
- Paid lot at the trailhead and along the access road, with 37 standard spaces. A $5 daily permit or a $25 annual OSMP permit is required; pay at the self-service ParkMobile station (Gregory Canyon is zone 24700, at the base of Flagstaff Road) or online, valid at all OSMP fee trailheads that day. The lot is small and popular, so it fills early on weekends.
- Connects to
- Saddle Rock, Amphitheater, Ranger, and E.M. Greenman trails from the trailhead, plus Green Mountain's summit by way of the Ranger Trail and Flagstaff Mountain by way of Realization Point.
- Best season
- Spring for wildflowers and a shaded, wooded climb; fall for cool, quiet hiking. Because the canyon is shaded, snow and ice can linger on the trail well into the cold months, so bring traction in winter.
Gregory Canyon at a glance
Gregory Canyon sits at the base of Flagstaff Road in west Boulder, right where the city runs into the foothills. It's a wooded, shaded canyon and one of the busiest gateways into the Open Space and Mountain Parks (OSMP) trail network: from the trailhead you can start up toward Green Mountain, Saddle Rock, the Amphitheater, or Flagstaff Mountain. The Gregory Canyon Trail itself is short and steep, and it's often hiked as the first leg of a bigger loop rather than an out-and-back on its own.
The Gregory Canyon Trail route
OSMP describes the trail heading west past the junction with the Saddle Rock Trail and crossing a ridge with rock outcrops and wide views. From there it climbs to a saddle and drops into a drainage that ends at a dirt road leading up to Realization Point on Flagstaff. You'll hike through a forested mountainside the whole way, and in spring the canyon fills with wildflowers. OSMP doesn't publish an official length or elevation gain for the trail, but it's steep enough that most people treat it as real climbing, not a warm-up.
Parking and the fee
The trailhead has a small paved lot plus parking along the access road, 37 standard spaces in all, and it's a fee area. You'll need a $5 daily permit or a $25 annual OSMP permit. Pay at the self-service ParkMobile station at the trailhead (Gregory Canyon is zone 24700, at the base of Flagstaff Road) or buy a permit online ahead of time; a daily permit is good at every OSMP fee trailhead for that date, and the Flagstaff stations operate 5 a.m. to 9 p.m. Buying online in advance does not hold a space for you, and this lot is small and popular, so it fills early on weekends and busy mornings. Come at first light or have a backup plan.
Difficulty and what to expect
OSMP doesn't rate its trails, but the Gregory Canyon Trail is best thought of as moderate to hard: short, steep, and rocky in places. The upside of all that shade is that the canyon stays cooler than the exposed foothill trails on a hot afternoon. The flip side is winter, when snow and ice can linger on the shaded trail long after sunnier slopes have melted out, so carry traction in the cold months.
Hiking to Green Mountain and beyond
The classic bigger day from here links the Gregory Canyon Trail to the Ranger Trail and up to the Green Mountain summit, one of Boulder's signature foothill peaks. You can also connect to Saddle Rock and the Amphitheater near the trailhead, or continue to the dirt road toward Realization Point to tie into Flagstaff Mountain. However you loop it, carry water, check the forecast, and give yourself more time than the short trail length suggests, because the climbing adds up.
Dogs at Gregory Canyon
Gregory Canyon is a Voice and Sight area, so a well-controlled dog can be off leash if it meets OSMP's voice-and-sight standard and wears a City of Boulder Voice and Sight tag. If your dog doesn't have the tag or won't stay under control, it needs to be on a hand-held leash. Cleaning up after your dog is required by law, and there's a dog station at the trailhead to help.
Best season and time to go
Spring is lovely here for the wildflowers and the shaded, wooded climb, and fall gives you cool, quiet hiking as the crowds thin. Summer works too, since the tree cover keeps the canyon cooler than the open trails nearby; just start early to beat both the heat and the parking crunch. In winter, expect snow and ice in the shade and pack accordingly.
Nearby trails and guides
- Green Mountain: the summit this canyon is a gateway to, by way of the Ranger Trail.
- Flagstaff Mountain: connected uphill through Realization Point, with its own overlooks and trails.
- Chautauqua Park: the famous Flatirons meadow and trailhead just east along Baseline Road.
- All hikes in Boulder: the full hiking hub, sorted by difficulty.
Recommended nearby
A few local spots we'd point a Gregory Canyon morning toward.
[CLIENT SLOT: featured cafe near Gregory Canyon]
[One honest line: coffee or breakfast before an early trailhead start.]
[CLIENT SLOT: featured gear shop near the Flatirons]
[One honest line: traction, water, or a last-minute layer for the canyon.]
[CLIENT SLOT: featured spot for a post-hike meal]
[One honest line: where to eat or grab a drink after the climb.]
Gregory Canyon FAQ
How much is parking at the Gregory Canyon trailhead?
A $5 daily permit or a $25 annual OSMP permit is required to park at Gregory Canyon. You can pay at the self-service ParkMobile station at the trailhead (Gregory Canyon is zone 24700, at the base of Flagstaff Road) or online in advance. A daily permit is valid at every OSMP fee trailhead for that date, and the Flagstaff stations run 5 a.m. to 9 p.m.
Where does the Gregory Canyon Trail go?
OSMP describes it heading west past the junction with the Saddle Rock Trail, crossing a ridge with rock outcrops and views, then climbing to a saddle and dropping into a drainage that ends at a dirt road leading up to Realization Point. From the trailhead and its connections you can reach Green Mountain, Ranger, Saddle Rock, Amphitheater, and Flagstaff Mountain, which is why it's one of west Boulder's main gateway canyons.
Is the Gregory Canyon Trail hard?
It's short but steep. The trail climbs quickly and is rocky in spots, so most hikers would call it moderate to hard. OSMP doesn't assign official difficulty ratings, but the canyon is wooded and shaded, which makes the climb more pleasant on a hot day than the exposed trails nearby.
Can I bring my dog to Gregory Canyon?
Yes. Gregory Canyon is a Voice and Sight area, so a dog can be off leash only if it meets OSMP's voice-and-sight control standard and wears a City of Boulder Voice and Sight tag. Otherwise it must be on a hand-held leash. Picking up after your dog is required by law, and there's a dog station at the trailhead.
How do you hike to Green Mountain from Gregory Canyon?
The common route links the Gregory Canyon Trail to the Ranger Trail, which climbs to the Green Mountain summit. It's a full foothill hike with real climbing, not a quick stroll, so plan for a longer outing, carry water, and check conditions before you start.
Sources
Facts on this page are drawn from these authoritative sources: