Arapaho Glacier and South Arapaho Peak, Fourth of July Trailhead, Indian Peaks Wilderness Area, Colorado

Arapaho Glacier and South Arapaho Peak - 7.9 miles

Fourth of July Trailhead

Arapaho Glacier and South Arapaho Peak (13,397')

Arapaho Glacier and South Arapaho Peak (13,397')

Round-Trip Length: 7.9 miles (add 1 mile and +692' roundtrip to South Arapaho Peak)
Start-End Elevation: 10,172' - 12,705' (12,705' max elevation)
Elevation Change: +2,533' net elevation gain (+2,603' total roundtrip elevation gain)
Skill Level: Moderate-Strenuous
Dogs Allowed: Yes
Bikes Allowed: No
Horses Allowed: No
Related Trails:

Arapaho Glacier and South Arapaho Peak - 7.9 Miles Round-Trip

Arapaho Glacier is located in the Indian Peaks Wilderness between South Arapaho Peak (13,397') and North Arapaho Peak (13,502'). Arapaho Glacier is the largest in Colorado and primary benefactor of the Boulder Watershed. It measures nearly .5 miles wide, .25 miles long, covers approximately 60 acres, and is an estimated 200' thick in its accumulation zone. Because it's still moving, geologists classify it as a true glacier.

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A moderate 3.95 mile trail leads from Fourth of July Trailhead to Arapaho Glacier Overlook, which spans a saddle between South Arapaho Peak and an unnamed 13,038' peak to the east.

A good route continues .5 miles and 692' up to South Arapaho Peak with views across the Gore Range, Ten Mile Range, Rocky Mountain National Park and North Fork Middle Boulder Creek:

The trail rises steadily past the Indian Peaks Wilderness Backcountry board (.4 miles : 10,385') to the first of several pitched switchbacks (.55 miles : 10,461'). In .8 miles the trail levels across steep, open hillsides with views across the valley of Mount Neva (12,814') and Diamond Lake's outlet waterfall.

The trail narrows across the midsection of a steep waterfall (1 mile : 10,650') to the Diamond Lake - Arapaho Pass Trail split (1.15 miles : 10,752').

Bear right on the Arapaho Pass Trail, which straightens on a methodical climb up the north valley wall. It rises in a thinning forest with views over the North Fork of Middle Boulder Creek, a lush valley braided with snow-fed streams and ponds.

The trail relaxes through a krummholz flat (1.65 miles : 11,110') to the Arapaho Glacier Trail split (2.05 miles : 11,236'). Bear right and cross the creek. The trail narrows and twists through dense willow and krummholz that may obscure the path. Once through treeline it straightens, steepens, and clarifies on a northeast heading into the open alpine. 

The trail bends NW below the summit of S. Arapaho Peak on the final run up to the glacier overlook.

Arapaho Glacier Overlook (3.95 miles : 12,705') stands nearly 500' above the glacier's base. Two large tarns and a string of lakes - all part of the Boulder Watershed - form from the glacier's ablation zone. If not summiting South Arapaho Peak, consider a short distance up the eastern saddle for wider views of the glacier.

The Arapaho Glacier Trail bends east from the Overlook and drops back to its terminus at the Glacier Rim Trailhead at Rainbow Lakes Campground.

To reach South Arapaho Peak, continue west on a social trail toward the summit. The trail soon loses clarity amid the talus, but rock cairns and an intuitive heading will keep you on track.

The trail clears 13,000' at 4.2 miles and moderates over false summits on a free scramble to South Arapaho Peak (4.5 miles : 13,397'). Two rock wind shelters and a peak finder are on the summit.

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Interactive GPS Topo Map

Key GPS Coordinates - DATUM WGS84

  • N39 59.714 W105 38.052 — 0.0 miles : Fourth of July Trailhead
  • N40 00.036 W105 38.346 — .55 miles : Begin switchbacks
  • N40 00.252 W105 38.785 — 1.15 miles : Arapaho Pass Trail junction
  • N40 00.426 W105 39.122 — 1.5 miles : Steady climb on straight northwest heading
  • N40 00.626 W105 39.512 — 2.05 miles : Arapaho Glacier Trail junction
  • N40 00.696 W105 39.287 — 2.5 miles : Clear krummolz and willow on NE heading
  • N40 00.645 W105 38.969 — 3.0 miles : Steady travel in open alpine hillside
  • N40 00.744 W105 38.694 — 3.5 miles : Gradual turn toward base of S. Arapaho Pk
  • N40 00.955 W105 38.645 — 3.95 miles : Arapaho Glacier Overlook
  • N40 01.044 W105 38.845 — 4.2 miles : Pass through 13,000' en route to summit
  • N40 01.180 W105 38.981 — 4.5 miles : South Arapaho Peak

Worth Noting

  • A glacier is a perennial mass of snow or ice that's large and heavy enough to flow, like a very thick gel. Glaciers form where more snow accumulates than is lost each year. The weight of new snow accumulation compresses older layers into ice, adding weight and thickness that perpetuate the growth cycle. This is called the accumulation zone, which occurs on the upper portion of a glacier.

  • A true glacier is in constant motion, and ice in the accumulation zone flows down to lower elevations, which is called the ablation zone. The ablation zone is located in the lower part of the glacier where more snow is lost than accumulates. Pools, or tarns, typically form at the base of an ablation zone.

  • North Arapaho Peak (13,502') is the highest mountain in the Indian Peaks Wilderness Area. Reaching it from South Arapaho Peak requires a precarious and laborious scramble down and up a .5 mile saddle between the two peaks. Only experienced and prepared climbers should attempt this summit.

  • Much of the hike to Arapaho Glacier runs above treeline. Anticipate strong sun, wind, cool temperatures, and rapidly changing weather conditions. Carry versatile layers, sun protection, and ample water. Get an early start to avoid afternoon thunderstorms.

  • Arapaho Glacier's melt feeds a string of lakes - Triple Lakes , Goose Lake, Island Lake, and Silver Lake - which hold most Boulder's water supply.

Camping and Backpacking Information

  • Permits are required for all overnight campers June 1 - September 15.

  • Permits are required year-round for day and overnight use by large groups (8+) or organizational groups such as scouts, churches, schools and hiking clubs.

  • Group size is limited to 12 people or people and packstock combined.

  • Campfires are prohibited east side of the Continental Divide, as well as Caribou Lake, Columbine Lake, Gourd Lake, Crater Lake and in the Cascade Creek drainage above Cascade Falls.

  • Camping is permitted only at designated campsites in the Diamond, Jasper, Crater and Caribou Lakes Backcountry Zones.

  • Camping is prohibited in the Four Lakes Backcountry Zone (Mitchell, Blue, Long, Isabelle) May 1 - Nov 30.

  • Camping is prohibited within 100' of lakes, streams and trails.

  • Packstock is prohibited in the Four Lakes Backcountry Zone, in the Cascade Backcountry Zone above Cascade Falls, and on the Diamond Lake Trail #975.

Fishing Information

  • Fishing is permitted at Diamond Lake, Dorothy Lake, Caribou Lake, and along North Fork Middle Boulder Creek with a valid Colorado state fishing license.

Rules and Regulations

  • Dogs must be on a hand held leash at all times.

  • Arapaho Glacier, Triple Lakes, Goose Lake, Island Lake, and Silver Lake comprise the Boulder Watershed and are off limits to the public. It's illegal to enter or recreate in the Boulder Watershed. It's the public's responsibility to know where these boundaries lie. Trespassing may result in fines and additional legal consequences.

Directions to Trailhead

Arapaho Glacier and South Arapaho Peak are accessed from the Fourth of July Trailhead in the Indian Peaks Wilderness near Nederland, Colorado.

From downtown Nederland, go south on Highway 72 for .5 miles to County Road 130 and make a right. You''ll see a sign for Eldora Ski Resort at this junction. Continue on Highway 130 through the town of Eldora, just past which it becomes a dirt road (4 miles).

Continue past the Hessie Trailhead another 4.8 miles and take the right fork at the Buckingham Campground into the designated parking area. Though suitable for most 2WD cars in good condition, the road between the Hessie turnoff and Fourth of July Trailhead can be rough. High clearance vehicles are recommended.

Contact Information

Boulder Ranger District
2140 Yarmouth Avenue
Boulder, CO 80301

Visitor Information
Phone: 303.541.2500


"Has anyone hiked Arapaho Glacier Trail/Glacier Rim Trail beginning at the Rainbow Lakes trailhead? "
Cyndee  -  Missouri  -  Date Posted: August 28, 2016
"Has anyone tried this trail during the month of January? My friends and I were looking at doing a couple of nights out in this area and are looking for a good place to hike/camp. We are all fairly experienced in hiking/outdoor survival/whatever new catch phrase for outdoors living. Any suggestions?"
Jeremy  -  NC  -  Date Posted: November 20, 2014
"Hi John, Did you click on the map link? We provide both an interactive Google Map as well as a printable / downloadable map. I just checked and both are there (the downloadable map also points out Diamond Lake - was that the confusion?). Best, Dave from PT"
Dave  -  Boulder  -  Date Posted: April 3, 2012
"need a map"
john stidman  -   -  Date Posted: April 3, 2012


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