Sourdough Trail to Brainard Lake Recreation Area, Sourdough Trailhead, Indian Peaks Wilderness Area, Colorado

Sourdough Trail to Brainard Lake Recreation Area - 11.6 miles

Sourdough Trailhead

Looking south from the Sourdough Trail

Looking south from the Sourdough Trail

Round-Trip Length: 11.6 miles
Start-End Elevation: 9,255' - 10,075' (10,305' max elevation)
Elevation Change: +820' net elevation gain (+1,676' total roundtrip elevation gain)
Skill Level: Moderate
Dogs Allowed: Yes
Bikes Allowed: Yes
Horses Allowed: Yes
Related Trails:

Sourdough Trail to Brainard Lake Recreation Area - 11.6 Miles Round-Trip

The Sourdough Trail stretches nearly 13 miles (south-north) from Rainbow Lakes Road to Camp Dick in the Roosevelt National Forest. This versatile trail runs along the eastern slopes of the Indian Peaks Wilderness, with mild grades ideal for runners, bikers and skiers.

Trail Map | Photo Gallery

The following describes the 5.3 mile section from Rainbow Lakes Road to the Red Rock Parking Area on Brainard Lake Road:

The trail heads north in a lodgepole forest until bending west (.75 miles) up the east flank of Niwot Mountain (11,471'). Note the introduction of spruce and fir as you gain elevation and cross from the upper-montane to subalpine zone.

These dense pine forests support deer, elk, bear, mountain lion and moose. The trail crosses Peace Memorial Bridge (2.5 miles : 9,924') over Four Mile Creek and switchbacks twice before resuming a steady pace and northerly heading.

The forest opens momentarily (4.0 miles : 10,282') with panoramas of the Peak-to-Peak Highway corridor, undulating with a net elevation loss to the Little Raven Ski Trail split (5.35 miles : 10,068').

Travel moderates over Left Hand Creek (5.7 miles : 10,071') to the Red Rock parking area on Brainard Lake Road (5.8 miles : 10,075'). Those with time may consider a short walk to Red Rock Lake, a popular fishing and camping destination.

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Interactive GPS Topo Map

Key GPS Coordinates - DATUM WGS84

  • N40 01.678 W105 31.494 — 0.0 miles : Sourdough Trailhead
  • N40 02.065 W105 31.641 — .5 miles mark
  • N40 02.098 W105 31.924 — 1.0 mile mark
  • N40 02.147 W105 32.349 — 1.55 mile mark
  • N40 02.343 W105 32.724 — 2.0 mile mark
  • N40 02.751 W105 32.735 — 2.5 mile mark
  • N40 02.862 W105 32.503 — 3.0 mile mark
  • N40 03.450 W105 32.357 — 3.75 mile mark
  • N40 04.015 W105 32.205 — 4.5 mile mark
  • N40 04.509 W105 31.987 — 5.35 miles : Little Raven Ski Trail junction
  • N40 04.799 W105 32.054 — 5.8 miles : Red Rock Parking Area on Brainard Lake Road

Worth Noting

  • Water is limited to two small creeks along this section of the Sourdough Trail. They're located 2.5 miles (Four Mile Creek) and 5.7 miles (Left Hand Creek) north of the Sourdough Trailhead.

  • Blue Tags on trees mark the entire trail, a useful winter navigational aid.

Camping and Backpacking Information

  • Dispersed camping is permitted along the Sourdough Trail. No permits are required. There are no designated sites, however many are well established from regular use along the trail.

  • Group sizes are limited to 12 individuals. *Permits are required for professionally guided groups or those of 12+ combined individuals and stock.

  • Fires are permitted unless otherwise indicated. Call in advance for status.

  • Camp at least 200' from the trailhead, trail and creeks.

Rules and Regulations

  • Dogs are not permitted between the Sourdough Trailhead and Red Rock Parking Area December 1 - May 1.

  • Snowmobiles are not permitted north of the 1.75 mile mark.

Directions to Trailhead

The Sourdough Trailhead is located .4 miles west of Highway 72 on the south side of Rainbow Lakes Road (a.k.a. County Road 116 - National Forest System Road 298). Rainbow Lakes Road is located 7.35 miles north of Nederland, CO.

Contact Information

Boulder Ranger District
2140 Yarmouth Avenue
Boulder, CO 80301

Arapaho and Roosevelt National Forests
2150 Centre Ave., Building E
Fort Collins, CO 80526

Trip Reports

There are no trip reports on this trail.


"I believe there’s an error in the “rules and regulations” section - based on the winter map of the area, dogs are allowed on the sourdough trail (it’s one of the only trails out of Brainard Lake that they are allowed on). Here’s the map - notice the little dog symbol on both sections of sourdough trail."
Lydia  -  CO  -  Date Posted: February 25, 2018
"I was hiking this trail yesterday and wondered off the trail at various points, I found various pits that were dug by hand. I was wondering if anyone know what these are?"
R. Barile  -  Thornton, CO  -  Date Posted: October 26, 2014
"This description has an error. All of sourdough is open to Bikes. Only the trails west in the Wilderness area are closed to bikes. Sourdough is a better biking trail than a hiking trail. If you are in the area, just go to Brainard Lake and start hiking west on on of the amazing trails there. "
Rich M.  -  Boulder  -  Date Posted: August 9, 2013


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