St Mary's Glacier, St Mary's Glacier Trailhead, Summit County - Eagle County - Clear Creek County, Colorado

St Mary's Glacier - 1.5 miles

St Mary's Glacier Trailhead

St Mary's Lake fed by the summer thaw of St Mary's Glacier

St Mary's Lake fed by the summer thaw of St Mary's Glacier

Round-Trip Length: 1.5 miles (x-country travel continues beyond glacier)
Start-End Elevation: 10,428' - 10,848' (at base of glacier)
Elevation Change: +420' net elevation gain (+467' total roundtrip elevation gain)
Skill Level: Easy-Moderate
Dogs Allowed: Yes
Bikes Allowed: No
Horses Allowed: No
Related Trails:

St Mary's Glacier - 1.5 Miles Round-Trip

St Mary's Glacier is located 9.2 miles north of Idaho Springs in the Clear Creek Ranger District of the Arapaho National Forest. The glacier - technically a large perennial snowfield - is a popular year-round destination open to hiking, skiing, glissading, climbing and sledding.

Trail Map | Photo Gallery

St Mary's Lake, located just below the glacier, is ringed by bristlecone pine, thick willow and abundant wildflowers. Though easily reached, exploring the glacier can be dangerous. Caution is a must for any activity - even casual walking - on the snowfield.

Important Note
The land through which you'll pass to reach St Mary's Lake and St Mary's Glacier is private. Landowners are not obligated to allow access, though they've permitted the public to do so for many years. Visitors should respect private land, stay on designated trails and pass with minimal impact. Fishing and camping may only take place on public lands north of the lake. It's the public's responsibility to know of and adhere to private property lines.


The trail heads northwest on a wide, rocky forest road. Keep left of all offshoots (these lead to private homes), and within clearly drawn property lines on each side of the road.

The road-trail rises quickly in a high subalpine forest that breaks suddenly at a bridge over St Mary's Lake outlet (.45 miles : 10,738'). Notable in this area are bristlecone pine, which thrive in extreme alpine environments and can live thousands of years.

The trail is somewhat vague but intuitively followed up the northeast shore of St Mary's Lake to the glacier. It narrows on a clearer path through dense willows and emerges on the north shore just below the snowfield where it melts into St Mary's Lake (.75 miles : 10,848').

The trail continues up the north side of the glacier over churned rocks and soil pushed to its margins by the annual growth and recession of the snow mass.

Footing can be tricky, and depending on the time of year, you may very well need to walk directly on the glacier to explore its upper reaches. You'll soon see a well-defined path on the glacier's south side, arguably a more stable option that's safely reached once grades moderate.

The snowfield tapers quickly up a narrow gulch that levels abruptly in vast open tundra (1.1 miles : 11,236'). Glass this expanse for elk, bighorn sheep and mountain goat.

James Peak (13,294') and Mount Bancroft (13,250') frame the west; James Peak is accessible by an unofficial but well-marked route that joins the Continental Divide Trail up to the summit.

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Interactive GPS Topo Map

Key GPS Coordinates - DATUM WGS84

  • N39 49.622 W105 38.606 — St Mary's Glacier Trailhead on CR 275
  • N39 49.946 W105 38.716 — .45 miles : Cross bridge over St Mary's Lake outlet
  • N39 50.116 W105 38.772 — .75 miles : Base of St Mary's Glacier
  • N39 50.259 W105 38.987 — 1.1 miles : Top of St Mary's Glacier

Worth Noting

  • It's approximately 8.3 miles roundtrip from the St Mary's Glacier Trailhead to the summit of James Peak.
  • The Rockies have been shaped by the cyclical growth, recession and reconstitution of glaciers over many millenniums. Glacial movement grinds the land beneath it, depositing till on its margins that accumulate on ridges called moraines. Wide, flat depressions sometimes form where glaciers end their downhill progression, ringed by the land (moraines) they've displaced.
  • Arrive early to secure parking and avoid crowds. The glacier is typically very busy on weekends.

Camping and Backpacking Information

  • Contact the Clear Creek Ranger District (303.567.3000) for the latest trail conditions and access restrictions before setting out.

  • Camping may only take place on public lands north and west of the lake. It's the public's responsibility to know of and adhere to private property lines.

  • Dispersed backcountry camping is permitted in the Arapaho National Forest. No permit is necessary. Camping is prohibited within 150' of any lake or stream. Group size is limited to 15 individuals.

  • Campfires are permitted for dispersed camping in the backcountry, with potential seasonal restrictions. Campfires are not permitted above or within .25 miles of treeline, or within 150' of any lake or stream.

Fishing Information

  • Fishing is permitted at St Mary's Lake, but only along its north shore, which is public land. It's illegal to fish from the south and east shores, which are private lands.

  • St Mary's Lake supports a naturally reproducing population of brook trout. The statewide, daily bag limit for brook trout is 10 fish (8 inches in length or less). The Colorado DOW does not stock St Mary's Lake.

Rules and Regulations

  • Parking along Country Road 275 (Fall River Road), while tolerated by private land owners and local authorities, is illegal. Fines, towing and booting are possible consequences for improperly parked cars.
  • Bikes and mechanized vehicles are not permitted at St Mary's Lake or St Mary's Glacier
  • Dogs are permitted but must be leashed, especially when passing through private property.

Directions to Trailhead

St Mary's Glacier is located in the Clear Creek Ranger District of the Arapaho National Forest. The St Mary's Glacier Trailhead is located 9.2 miles north of I-70 on SR 275 (Fall River Road).

From I-70, exit #238 for St Mary's - Alice - Fall River Road. From the exit ramp, turn north on CR 275 and drive 9.2 miles to the St Mary's Glacier Trailhead on the left (west) side of the road. Roadside parking is restricted (see rules and regulations above). The trail begins on a wide, rocky forest road marked by a large white sign clearly visible from the road.

Contact Information

Clear Creek Ranger District
101 Chicago Creek Road
P.O. Box 3307
Idaho Springs, Colorado 80452
Open daily 8-4:30, Open holidays

Trip Reports

There are no trip reports on this trail.


"Was this once a dude ranch back in the late 1940s? I remember it as Glacier Lake or Lake Glacier. Thanks for any information you may have..."
Austin Snyder  -  Kentucky  -  Date Posted: June 6, 2017
"Lovely hike, short up to the actual glacier but well worth it. Plenty of areas to climb around after the lake and an amazing view! The lake and overlooks are just magnificent, also very windy and chilly up there this time of year. Rocky climb most of the way up to the lake where it levels out, if you decide to climb up the glacier then it does get steeper and rockier but it is a lot of fun. Good easy-moderate hike for adults and children, dogs allowed too!"
 -   -  Date Posted: October 8, 2012


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