Breckenridge, CO: McCullough Gulch Trail to Pacific Tarn

Just two hours from Denver, this 7.4-mile out-and-back passes several waterfalls en route to a magnificent lake basin that provides off-trail access to Pacific Tarn, the highest officially named lake in the United States.
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As the editor of BACKPACKER, I'm always on the lookout for great new hikes to take with my wife and daughters on the weekend. Discovering this route was an accident -- I was scanning the area south of Breckenridge, which I hadn't visited before, with peakbagging in mind. By chance, I saw this lake, which looked really, really high. It was tucked into a small hanging valley just north of Quandary Peak, which I knew would see a lot of traffic on Labor Day weekend. As I zoomed in on the terrain in Google Earth, a Wikipedia note popped up explaining that this lake had been studied and then officially named by a scientist from Boulder named Carl Drews in 2004. Pacific Tarn is a bit bigger than a football field, and it sits at 13,420 feet. The view looking east is spectacular--like an infinity pool, the lake laps almost to the edge of a steep drop on its eastern edge, providing dramatic vistas from the Tenmile Range (where it is) to a jumble of sharp 12,000-footers about 10 miles away. And the hike to it, especially the section between 11,500 and 13,000 feet, is all classic alpine beauty -- a broad valley carpeted in tundra and wildflowers, dotted with meltwater pools, in the shadow of a picket-fence of jagged peaks rising as high as 14,271 feet (Quandary Peak). Best of all: You might have the entire valley to yourself. Because it's close to Quandary Peak, an easy Colorado 14er just 20 minutes south of Breckenridge, this valley gets little traffic beyond the first two miles (which dayhikers use to visit White Falls and a gorgeous unnamed lake a quarter-mile above it). Warning: The crux section of this hike is a very loose and steep talus field that contains significant rockfall hazard and decent risk of uncontrollable falls. Use extra caution in placing hands and feet, and do not climb directly below other hikers.

From the trailhead, take the McCullough Gulch Trail (named for the ravine you're ascending) west, passing the locked gate, crossing the creek on a wooden bridge, and climbing steeply right away. The trail follows a dirt mining road for a half-mile before turning to the left onto singletrack. The path ascends at a more mellow (but still steady) grade through lodgepole pines and a few aspen, then crosses a small boulderfield, before crossing a log bridge and reaching the junction to White Falls at .9 mile. Drop your pack for the short side trail to the cascade, which slides in sparkling ribbons over several hundred feet of dark, moss-draped rock.

From this junction, the pitch steepens again as you pick your way through rockier terrain--soon passing treeline--covered with tundra grasses and tiny wildflowers. About one-third of a mile above the falls, the maintained trail crests and ends at a picture-perfect lake that provided us with a dramatic rainbow moment (see photo gallery). A use trail continues on the north side of the lake, which one branch leading to a little-used climbing route of Quandary Peak at the back of the valley. The other branch--which is much fainter--heads northwest towards Pacific Tarn, but peters out well short of it. To reach Pacific Tarn, you must hike cross-country to the obvious ridge north of the lake, then drop slightly into a very large boulder field that you must cross to reach the obvious headwall/gulley/pass leading to Pacific Tarn. Numerous spots along the way make superb at-large campsites; water is plentiful, and the views of Quandary Park are dwarf-to-giant immense.

Use extra caution in crossing the boulder field and ascending the gulley to Pacific Tarn: The rock is very loose, and snowfields often last on the gulley year-round. Technical skills and climbing gear are not needed--it's a steep, sketchy walk--but do not cross or walk beneath other hikers due to the risk of rockfall.

Once you scale the wall, you'll discover it's a false summit. You still have 300 vertical feet to climb to see Pacific Tarn, which sits at 13,400 feet and just behind the small ridge to your north. Head straight up the middle by the best route you can scout; there's no use trail here due to the very limited traffic.

--Mapped by Jonathan Dorn

Trail Facts

  • Distance: 11.9



Location: 39.400873, -106.078734

Trailhead: Park at the locked gate (but don't block it!) at the end of McCullough Gulch Road.


Location: 39.401164, -106.08198

Evidence of mining activity is all around on the lower part of the hike, including this cabin. Do not trespass on private property.


Location: 39.403638, -106.085559

Turn left onto singletrack, leaving the dirt mining road.


Location: 39.404827, -106.087034

Stay straight, following small cairns, where the trail threads through the boulders.


Location: 39.406473, -106.092376

Head left for spur trail to White Falls. Turn right to continue uphill on the McCullough Gulch Trail.


Location: 39.405994, -106.093177

White Falls


Location: 39.406539, -106.097009

The trail levels off a bit here after steep climbing; your reward are superb views of and across a glacial lake.


Location: 39.407749, -106.099906

After a nice respite, the trail climbs again.


Location: 39.405925, -106.105828

Congratulations: You've reached the main valley to the north of Quandary Peak and a great place to scout for off-trail campsites.


Location: 39.414861, -106.118896

Facing the gulley, you'll likely have several choices, either following a route to the left through some small rock towers, or heading straight up the middle. We did both, and neither is markedly better, though the middle section is potentially more hazardous due to the snowfields that linger there year-round.


Location: 39.413568, -106.117845

User trail: Here you'll see a series of cairns and a flat path (old miner's trail, probably) amidst the rocks about here.


Location: 39.418667, -106.121883

This spot is about 200 feet above Pacific Tarn, the highest named lake in the United States. You can descend easily to the shore if you wish. Backtrack to trailhead.

Rainbow over unnamed lake

Location: 39.407053, -106.098361

This 'bow formed about 5 minutes earlier. Knowing the lake was just ahead, I took off running up the trail (steep!) and arrived at the west end of the lake just in time to snap off four or five photos as my wife and kids crested the ridge on the other side--with the rainbow coming right down on them. This is one of my favorite photos ever.

Gate at trailhead

Location: 39.401117, -106.078491

McCullough Gulch trailhead sign

Location: 39.400951, -106.07862

Handcarved detail on trailhead sign

Location: 39.400918, -106.07862

Miner's cabin

Location: 39.400918, -106.081796

Sign in front of miner's cabin

Location: 39.401216, -106.081753

First views of Quandary Peak

Location: 39.402311, -106.083126

White Falls

Location: 39.405991, -106.092868

Looking back down valley

Location: 39.407119, -106.095572


Location: 39.406124, -106.10733

We pitched our tents in this area, but if we hadn't been tired with sunset looming, we would've explored farther up the meadow.

Looking west from camp

Location: 39.406025, -106.107073

Looking south from camp at Quandary Peak

Location: 39.406025, -106.107159

The world's smallest mountain dog

Location: 39.414844, -106.11866

Trudy, the amazing one-year-old miniature wiener dog, hiked every part of this route except the steep gully ahead.

User trail

Location: 39.414778, -106.118917

Cairns mark a short, old miner's path

Easier tundra walking above the gulley

Location: 39.415441, -106.121922

Pacific Tarn from above

Location: 39.41869, -106.121922

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