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Running trails & routes
United States
Colorado
Clear Creek County
St. Mary's

St. Mary's Glacier Trail

Hard

4.9

(8273)

8,274

runners

St. Mary's Glacier Trail

00:34

3.27km

200m

Running

The St. Mary's Glacier Trail offers a unique alpine experience, quickly ascending through pine and aspen forests to the scenic St. Mary's Lake. Beyond the lake, the path steepens considerably, leading to the year-round St. Mary's Snowfield, often mistakenly called a glacier. You'll find stunning panoramic views of the Rocky Mountains and Front Range, with wildflowers and small waterfalls enhancing the scenery in spring.

This 2.0-mile (3.3 km) route is rated difficult, with a significant 661 feet (201 metres) of elevation gain that most will cover in around 34 minutes. The high altitude, starting around 10,000 feet, adds to the challenge, making it feel more strenuous than its length suggests. Parking at the trailhead requires a fee, and due to its popularity, especially on weekends, an early start is advisable.

What truly sets this trail apart is the accessibility to a year-round snowfield, making it a popular spot for summer skiing and snowboarding just an hour from Denver. Despite its relatively short length, it delivers impressive "big Colorado scenery" with minimal effort, offering a rewarding outing for those seeking a challenging, high-altitude jog or hike.

Last updated: June 9, 2026

Waypoints

A

Start point

Parking

Get Directions

1

1.04 km

Saint Mary's Lake

Highlight • Lake

Saint Mary's Lake is fed by the melting Saint Mary's Glacier. There is a paid parking area below the lake with restrooms and informational signs. The hike up to the lake is extremely popular, but the further you push past the lake, the fewer people you will encounter.

Tip by

2

1.62 km

Saint Mary's Snowfield

Highlight • Natural Monument

Saint Mary's Glacier actually isn't a glacier at all; it's simply a snowfield that doesn't completely melt in the warmer months. The persistence of snow throughout the year caused people to start referring to the snow mass as a glacier, but it isn't actually moving down the valley (which is the distinguishing feature of a glacier). This is still a cool feature to come check out any time of year.

Tip by

B

3.27 km

End point

Parking

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Way Types & Surfaces

Way Types

2.37 km

536 m

355 m

Surfaces

1.73 km

536 m

355 m

317 m

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Elevation

Elevation

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Weather

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Today

Monday 13 July

22°C

8°C

14 %

Additional weather tips

Max wind speed: 16.0 km/h

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Frequently Asked Questions

Where can I park for the St. Mary's Glacier Trail?

The trailhead is located about an hour from Denver, near Idaho Springs. There is a designated parking area, but it can fill up quickly, especially on weekends and during peak season. Arriving early is highly recommended to secure a spot.

Is the St. Mary's Glacier Trail dog-friendly?

Yes, the trail is generally dog-friendly. However, as it's located within Arapaho National Forest, all dogs must be kept on a leash to protect wildlife and ensure a pleasant experience for all trail users. Be mindful of the rocky terrain and potential for snow, which can be tough on paws.

Do I need a permit or pay an entrance fee to access the trail?

The St. Mary's Glacier Trail is located within the Arapaho National Forest. While there isn't typically an entrance fee for the forest itself, there may be a fee for parking at the trailhead. It's always a good idea to check local regulations before you go, as conditions and rules can change.

What is the best time of year to jog this trail?

The best time for jogging is typically late spring to early fall when the trail is relatively clear of snow and ice. However, snow can be present year-round, especially closer to the glacier. In winter, the trail can be snow-covered and icy, making jogging difficult and requiring specialized gear like microspikes or snowshoes.

What can I expect the terrain to be like?

The terrain is largely a singletrack with a noticeable and often steep incline from the start. It's quite rocky throughout, requiring careful footing. The initial section winds through a forest before opening up. As you ascend towards the lake and the glacier, the terrain becomes even steeper and rockier. Conditions vary with the season, with snow and ice possible year-round.

How difficult is this trail for jogging?

While rated moderate for hiking, for jogging, this trail leans towards difficult. It features significant elevation gain over a short distance, starting at approximately 10,300 feet. The first stretch is a 'lung burner' even for hikers, making it particularly challenging for sustained jogging, especially for those not acclimated to high altitude.

What scenic highlights will I see along the route?

You'll ascend through a beautiful forest of pine and aspen trees. Upon emerging, you'll be treated to views of Saint Mary's Lake, a clear alpine lake. Beyond the lake, the main attraction is the Saint Mary's Snowfield, which retains snow year-round. Panoramic vistas of the surrounding Rocky Mountains are a constant reward.

Does the trail intersect other well-known paths?

Yes, the route also passes through sections of the St Marys Glacier Hike, St. Mary's Glacier Trail, Fox Court, and Canyon Court.

What should I wear and bring for a jog on this trail?

Given the high altitude and variable conditions, layers are essential. Bring sturdy trail running shoes with good grip for the rocky terrain. Even in summer, a light jacket is advisable. Water, snacks, sun protection, and a map or GPS are also highly recommended. In colder months or if snow is present, microspikes or snowshoes might be necessary.

Is it possible to jog to the actual glacier?

The 'glacier' is technically a semi-permanent snowfield that retains snow year-round. You can jog towards it, but the terrain becomes increasingly steep and rocky as you approach. Depending on conditions, you might need to transition to hiking or use specialized gear to safely reach the snowfield itself.

Is this trail suitable for beginner trail runners?

Due to its steepness, rocky terrain, and high altitude, this trail is generally not recommended for beginner trail runners. It's best suited for those with experience in mountain running and good physical conditioning. Beginners might find it more enjoyable as a challenging hike.

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