Thunder Lake, Wild Basin Trailhead, Rocky Mountain National Park, Colorado

Thunder Lake - 13.2 miles

Wild Basin Trailhead

Thunder Lake (10,574')

Thunder Lake (10,574')

Round-Trip Length: 13.2 miles
Start-End Elevation: 8,510' - 10,574' (10,676' max elevation)
Elevation Change: +2,064' net elevation gain (+2,318' total roundtrip elevation gain)
Skill Level: Moderate-Strenuous
Dogs Allowed: No
Bikes Allowed: No
Horses Allowed: Yes
Related Trails:

Thunder Lake - 13.2 Miles Round-Trip

Thunder Lake (10,574') is located 6.6 miles from Wild Basin Trailhead in Rocky Mountain National Park. It lies just below treeline in an open basin with excellent fishing and numerous backcountry campsites.

Trail Map | Photo Gallery

This long but moderate trail follows North St Vrain Creek through dense forest with stops at Copeland Falls, Calypso Cascades and Ouzel Falls.

An unmaintained route continues past Thunder Lake to Boulder Grand Pass on the Continental Divide (12,061'), which joins the East Inlet Trail to form a challenging E-W thru-hike across the Park:

The trail rises gently beside North St Vrain Creek to spurs for Lower and Upper Copeland Falls (.35 and .45 miles). Mild travel continues to the backcountry campsite access trail (1.35 miles : 8,860'), crosses the creek and climbs .45 miles to Calypso Cascades (1.8 miles : 9,108').

The trail wraps up a north-facing valley wall and passes through an area stricken by lightning-induced fire in 1978 (2.1 miles : 9,100').

Despite significant damage, the forest is in a natural state of recovery. Grasses and wildflowers brighten the hillsides, while young aspen and lodgepole emerge in replenished soils. In time, spruce and fir will overtake them and return the forest to its ecological climax.

The trail steepens to Ouzel Falls (2.6 miles : 9,366'), drops and rises back to the Ouzel Lake - Thunder Lake Trail split (2.95 miles : 9,418'). Follow signs for Thunder Lake. The trail undulates higher and crosses back over the creek to its 2nd connection with the backcountry campsite access trail (3.35 miles : 9,505').

Here it steadies and straightens on a northwest heading for 1.4 miles to the Thunder Lake - Lion Lake Trail split (4.7 miles : 10,025'). Make good time on this pleasant but unspectacular stretch to allow more time for difficult segments ahead, and exploration of the lakes.

The Thunder Lake Trail bends northwest and steepens into a thinning forest that reveals an attractive network of ponds, streams, and meadows. Mahana Peak (12,632'), Tanima Peak (12,420') and Pilot Mountain (12,222') can be seen at different points on the final ascent.

The trail veers left at the Thunder Lake Group Campsite spur (6.45 miles : 10,676' - the trail's highest point) and drops to Thunder Lake (6.6 miles : 10,574').

Thunder Lake is framed by Tanima Peak (south), and Pilot Mountain and Mount Alice (13,310') to the NW. Ponds and flowers dot Thunder Lake's outlet area, and thinly treed knolls on the lake's edge create secluded nooks - allow to time to explore this scenic area. A Ranger Patrol Cabin on the lake's NE side posts useful area information.

An unimproved but well-formed trail continues 1.45 miles and 1500' above Thunder Lake to Boulder-Grand Pass (12,061') on the Continental Divide.

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Interactive GPS Topo Map

Key GPS Coordinates - DATUM WGS84

  • N40 12.469 W105 33.993 — 0.0 miles : Wild Basin Trailhead
  • N40 12.230 W105 34.391 — .45 miles : Spur to Upper Copeland Falls
  • N40 12.022 W105 35.293 — 1.35 miles : Backcountry campsite access trail split #1
  • N40 11.731 W105 35.426 — 1.8 miles : Calypso Cascades
  • N40 11.939 W105 35.788 — 2.25 miles : Pass thru Ouzel Fire burn area
  • N40 11.919 W105 35.981 — 2.6 miles : Ouzel Falls
  • N40 12.094 W105 36.197 — 2.95 miles : Ouzel Lake and Bluebird Lake Trail junction
  • N40 12.303 W105 36.403 — 3.35 miles : Backcountry campsite access trail split #2
  • N40 12.493 W105 37.057 — 4.0 miles : Fast travel on mild grades
  • N40 12.771 W105 37.502 — 4.7 miles : Thunder Lake - Lion Lake Trail split
  • N40 12.771 W105 37.871 — 5.15 miles : Steady, steep climb into subalpine forest
  • N40 13.094 W105 38.242 — 5.65 miles : Grade moderates
  • N40 13.239 W105 38.240 — 5.85 miles : Cross Creek
  • N40 13.382 W105 38.266 — 6.0 miles : Pass through meadow in thinning forest
  • N40 13.424 W105 38.655 — 6.45 miles : Thunder Lake backcountry campsite spur
  • N40 13.329 W105 38.706 — 6.6 miles : Thunder Lake

Worth Noting

  • Lion Lake is a more demanding but commensurately rewarding alternative to Thunder Lake. Stock is not permitted up to Lion Lake, and there are no designated backcountry campsites. Consider Lion Lake during peak summer months for greater solitude.
  • Bears are common in the Wild Basin Area, and their activities occasionally close backcountry campsites en route to Thunder Lake. Call ahead for status, and follow food storage and encounter protocols.
  • Though moose are uncommon on the east side of Rocky Mountain National Park, you may find them in the Wild Basin high country. Moose, which are numerous on the Park's west side, sometimes migrate east over mountain passes once clear of snow. Moose can be aggressive during the rut, with calves, or when startled. Enjoy wildlife from a distance, and allow animals plenty of room to pass.

Camping and Backpacking Information

Backcountry Camping in Rocky Mountain National Park

  • A permit is required for all backcountry camping in Rocky Mountain National Park. Permits may be obtained from the Beaver Meadows Visitors Center Backcountry Office, or the Kawuneeche Visitor Center at Grand Lake. Day-of-trip permits may be obtained in-person, year round.
  • There's a $26 fee to backcountry camp in Rocky Mountain National Park (May 1 - October 31). This administrative fee covers each party (defined as an individual or group) for the duration of the trip. Note that park entrance fees are applied separately and in full.

Backcountry Campsites in the Wild Basin Area

Pine Ridge Backcountry Campsite

  • The Pine Ridge site is located 1.4 miles from Wild Basin Trailhead at 8,880'. There are 2 individual sites and a privy. 2 backcountry sites are located in a lodgepole forest north of the trail, just east of the bridge across North St. Vrain Creek. A food storage cable is about 8 steps past the spur to site #1. It's in a small clearing to the left and runs perpendicular to the trail. Obtain water from North St. Vrain Creek.

Tohosa Backcountry Campsite

  • The Tohosa site is located 1.7 miles from Wild Basin Trailhead at 9,040'. There is 1 individual site and no privy. The site is located .3 miles up the unimproved, backcountry campsite access trail in a lodgepole stand at the edge of a small rocky bluff. Obtain water from North St. Vrain Creek, approx. 160 yards downhill from the site.

Aspen Knoll Backcountry Campsite

  • The Aspen Knoll site is located 2.3 miles from Wild Basin Trailhead at 9,400'. There is 1 individual site and no privy. The site is located along the unimproved, backcountry campsite access trail in a mixed aspen-spruce-lodgepole forest. Obtain water from North St. Vrain Creek, approximately 200 yards downhill from the site.

Siskin Backcountry Campsite

  • The Siskin site is located 3.2 miles from Wild Basin Trailhead at 9,460'. There is 1 individual site and no privy. The site is located along the unimproved, backcountry campsite access trail in a lodgepole stand. Obtain water from North St. Vrain Creek, approx. 135 yards downhill from the site.

North St Vrain Backcountry Campsite

  • The North St Vrain site is located 3.5 miles from Wild Basin Trailhead at 9,560'. There are 2 individual sites and a privy. The sites are located along the unimproved, backcountry campsite access trail, right near where it rejoins the main trail. A food storage cable is located 20 steps up the access trail in a small clearing on the left, and parallel to the trail. The sites lie in a thick lodgepole stand on the north side of the trail, just after it crosses North St. Vrain Creek. Obtain water from North St. Vrain Creek.

Thunder Lake Backcountry Campsite

  • The Thunder Lake site is located 6.6 miles from the Wild Basin Trailhead at 10,574'. There are 3 individual sites, 1 group site, and 1 stock site. The individual sites are located in a forested area north of the trail about 300 yards east of the lake. The stock site is about 100 yards from the lake on the south side of the trail and slightly east of the hitchrack. Obtain water from Thunder Lake's outlet stream.

Fishing Information

  • A valid Colorado fishing license is required for all persons 16 years of age or older to fish in Rocky Mountain National Park. No other permit is required, however, special regulations exist. It's your responsibility to know and obey them. Due to the dynamic nature of fisheries management, fishing regulations can change at anytime. Special closures may be put in place above and beyond what is listed here. Contact the park before heading out for current information.
  • Method of Capture: Each person shall use only one hand-held rod or line. A 'second rod stamp' is not honored in park waters. Only artificial lures or flies with one (single, double, or treble) hook with a common shank may be used. "Artificial flies or lures" means devices made entirely of, or a combination of, materials such as wood, plastic, glass, hair, metal, feathers, or fiber, designed to attract fish.
  • This does not include: (a) any hand malleable material designed to attract fish by the sense of taste or smell; (b) any device to which scents or smell attractants have been externally applied; (c) molded plastic devices less than one and one-half inch in length; (d) foods; (e) traditional organic baits such as worms, grubs, crickets, leeches, minnows, and fish eggs; and (f) manufactured baits such as imitation fish eggs, dough baits, or stink baits. Fly fishers may utilize a two hook system, where one hook is used as an attractant.
  • While in possession of any fishing equipment, bait for fishing (insects, fish eggs, minnows, or other organic matter) or worms is prohibited. Children 12 years of age or under, however, may use worms or preserved fish eggs in all park waters open to fishing except those designated as catch-and release areas.
  • No bait or worms are allowed in catch-and-release waters.
  • Use of lead sinkers (or other lead fishing materials) is strongly discouraged.

Rules and Regulations

  • A $20 Day Use Fee is required to enter Rocky Mountain National Park (or $30 for a 7 Day Pass).
  • Dogs are not permitted on hiking trails in Rocky Mountain National Park.

Directions to Trailhead

Thunder Lake is accessed from the Wild Basin Trailhead in Rocky Mountain National Park. The trailhead is located 2.3 miles west of Highway 7 between the towns of Allenspark and Estes Park.

From Estes Park, head south on Highway 7 for 11 miles to the Wild Basin turnoff on the west side of the road. Turn west on the dirt road to the entrance station .15 miles ahead. The Wild Basin Trailhead is located 2.15 miles from the entrance station. Parking is limited, and roadside restrictions are strictly enforced.

Contact Information

Rocky Mountain National Park
Visitor Information:

Backcountry Office:

Campground Reservations:

Trip Reports

There are no trip reports on this trail.


"Amazing trail. Packed snow and dirt until the Pine Ridge Campsite, then the trail turned into a runoff stream with plenty of snow and post holing for a challenge."
Batman  -  Denver  -  Date Posted: May 5, 2015
" Packed in with horses and had 3 days of decent fly fishing. Abundant flora and wildlife. 103 F in Denver and 60's at camp. The trail was easy but steep.Had a great time."
Eric  -  Minnesota  -  Date Posted: July 17, 2013
"Overnight backpack to Thunder lake. First night at St. Vrain. Side trip to Ouzel Falls. "
 -   -  Date Posted: October 7, 2012
"Nice hike to Thunder. Good workout, not too tough. The real fun/challenge was going up to Lake of Many Winds. Even in late August there was snow and icebergs (cool formations - a whale and a submarine) in LoMW."
 -   -  Date Posted: May 24, 2012


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