Trail Description

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Resting on the steep slopes of Apache (13,441') and Shoshoni (12,967') peaks is Isabelle Glacier, the origin of South Saint Vrain Creek and Lake Isabelle's main benefactor. The short hike to Lake Isabelle is one of the Indian Peaks' most popular, however few venture higher into the pristine glaciated valley that frames it. While the trail to Lake Isabelle is relatively mild, conditions are incrementally challenging in the upper valley: hikers should anticipate periods of steep, talus-riddled terrain from the lake’s west edge to Isabelle Glacier's base. Visitors will enjoy brilliant wildflowers, breathtaking alpine scenery and an intimate look at this impressive glacial formation.

From the Long Lake Trailhead, a well-groomed path loosely follows the north shore of Long Lake beneath stately spruce to the first of two connections with the Jean Lunning Trail (.2 miles : 10,524'). It undulates mildly to the second Jean Lunning Trail connection (1.2 miles : 10,674’), continuing with similar facility through a break in the forest with views of the dramatic upper-valley ahead (1.6 miles : 10,716’). The trail begins a more deliberate climb (1.85 miles) in a progressively thinning forest to Lake Isabelle’s lively outlet area (2.05 miles : 10,908’).

The stream-crossed, flower-lined trail crests a small ridge and drops gently to Lake Isabelle and Pawnee Pass Trail junction (2.1 miles : 10,892'), a visually stunning area near treeline worth exploring on your return. The trail continues along and above Isabelle’s idyllic north shore before dropping abruptly into the basin to avoid a talus field on its northwest corner (2.4 miles). After a brief reprieve on the lake’s verdant west fringe (2.6 miles) the trail climbs steeply beside Isabelle’s tumbling inlet falls to a level bench (2.9 miles : 11,083’), followed quickly by a similar push to a second (3.15 miles : 11,273').

Here the landscape opens with liberating views of the upper and lower valleys; Isabelle Glacier is now visible in the northwest corner of the mountainous encasement ahead (a smaller, unnamed glacier lies beneath Navajo Peak’s 13,409’ summit to the south). Amid distracting beauty the trail bends sharply south (left) on a deliberate move across the valley (3.2 miles : 11,295’); though level remain vigilant, as markings are few and clarity is lost while piecing through marsh, willow, ponds and streams.

Trail conditions improve on the valley’s south side (3.45 miles : 11,360’), where a steep, winding course threads the vestiges of treeline to a third level tier at the foot of a scenic glacial tarn (3.75 miles : 11,460’).

The trail – now a rugged, uneven talus route marked sparingly by anonymous cairns - hugs the tarn’s north side while rising above to a misty cascade (3.95 miles : 11,560’); here it turns sharply right (north) on a sequence of strenuous, tightly-wound switchbacks into the narrow upper valley where Isabelle Glacier awaits. Pay close attention to cairns and routing, as the designated course offers the best available footing through this inhospitable terrain. The trail finally relents and bends west on the final approach, hopping over a trickling stream just shy of the glacier’s edge (4.2 miles : 11,915’).

A direct, intuitive scramble negotiates the last talus field to Isabelle Glacier’s base (4.35 miles : 12,025’) . From these heights you'll enjoy up-close views of Navajo, Apache and Shoshoni peaks, and the uniquely shaped rock pinnacles (gendarmes) between them. You can explore the glacier itself, though caution and light treading is a must on these unpredictable and occasionally unstable surfaces. A small tarn (snow covered and iced-over much of the year) lies below the glacier, an interesting excursion if travel conditions permit.

GPS Coordinates - DATUM WGS84

• N40 04.674 W105 35.077 - Long Lake Trailhead

• N40 04.550 W105 35.220 - 2 miles : Jean Lunning Trail junction #1

• N40 04.223 W105 36.083 - 1.2 miles : Jean Lunning Trail junction #2

• N40 04.167 W105 36.716 - 1.85 miles : Begin moderate switchbacks

• N40 04.225 W105 36.875 - 2.1 miles : Lake Isabelle and Pawnee Pass Trail junction

• N40 04.116 W105 37.406 - 2.6 miles : West end of Lake Isabelle

• N40 04.028 W105 37.671 - 2.9 miles : Tier 1 of inlet falls

• N40 03.930 W105 37.860 - 3.15 miles : Tier 2 of inlet falls - cross valley

• N40 03.753 W105 37.919 - 3.45 miles : Reach south side of valley

• N40 03.719 W105 38.162 - 3.75 miles : Edge of glacial tarn

• N40 03.734 W105 38.300 - 3.95 miles : Switchbacks @ cascade above tarn

• N40 03.793 W105 38.367 - 4.1 miles : Continue on switchbacks above tarn

• N40 03.790 W105 38.451 - 4.2 miles : Cross stream

• N40 03.799 W105 38.564 - 4.35 miles : Isabelle Glacier

Worth Noting

• Isabelle Glacier was named by Fred Fair, a Boulder City engineer who discovered the glacier in the early 1900s. He named both it and Lake Isabelle after his wife. When he died in 1935, his ashes were scattered over Isabelle and Fair glaciers.



• Snow may linger on the trail well into summer, compromising safety and routing. Check with the Forest Service for current conditions and trail information.



• Get an early start to avoid afternoon thunderstorms that are difficult to see coming over the Continental Divide. When storms are imminent, get below tree line as quickly as possible.

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.



• Pets must be on a handheld leash at all times.



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

Rules and Regulations

• There is a $9 fee to enter the Brainard Lake Recreation Area. Use the self-service pay station if no attendant is on duty. Fees, Parking, Pet, Camping and Trespassing regulations are strictly enforced.



• Dogs must be leashed at all times on trails within the Brainard Lake Recreation Area.

Directions to Trailhead

The Long Lake Trailhead is located within the Brainard Lake Recreation Area off of CO 72 (12 miles north of Nederland, just north of the town of Ward).

From Highway 72, turn west on Brainard Lake Road. In 2.6 miles you'll reach a pay station. Use the self-service pay station if no attendant is on duty. Continue another 3.2 miles on the paved road to the Long Lake Trailhead. This road may be closed at the halfway point from late October through late June or early July (depending on snow).

Long Lake can also be reached via the Niwot Cutoff Trail from the Niwot Cutoff Trailhead near the Niwot Mountain Picnic Area on the west end of Brainard Lake.

Contact Information

Boulder Ranger District
2140 Yarmouth Avenue
Boulder, CO 80301
303.541.2500