14.5 miles
3,307 ft
-3,302 ft
1 mile
High Point

The Bilk Mountain loop consists of a rarely used pair of non-motorized USFS trails along Avalanche Gulch Road in the Big Belts. It is a very challenging loop, with elements including heavy brush, downfall, minor trail-finding, a steep climb, a long undulating ridge section, and a fast and variable-condition downhill. The reward is huge views from many points of the ride, a very remote feel, and a fun descent that is not overly technical.

To get to the trailhead, take Canyon Ferry Road eastbound out of Helena. 8 miles past the dam, take a left on the USFS-signed Avalanche Gulch Road. Continue on the 2wd passable road for 5 miles to the Bilk Mountain Trailhead on the right.

To begin the ride, pedal up Avalanche Gulch for 3.4 miles until the valley widens and you see a sign (facing North) indicating the turn for Cayuse Mountain Trail #235. The trail starts on a sidehill before dropping to Cayuse Creek and crossing it at an old washed-out culvert. Then, the doubletrack climbs to a small meadow and turns right. Instead of turning, look for a faint singletrack heading to the left/straight and a USFS blaze. This is where the frustratingly thick overgrowth begins, which will slow your progress up the still easy to follow trail, which does not stray from the gulch bottom. The trail and creek take a right (south) turn and begin climbing more steeply. After switchbacking across the now trickle of a creek, the trail mostly disappears and you instead follow a very old and steep doubletrack road up the side of Cayuse Mountain.

Upon reaching the grassy saddle, there is a view to the southeast, and a forest service sign for the Cayuse Mountain Trailhead - which would require a very roundabout drive to get to. Turn right (south)
on doubletrack and go over a small hump before dropping off to the right on the Bilk Mountain Trail #232 at the remnants of a signpost. The trail descends and climbs frequently on the south face of Bilk Mountain, but does not reach the top. In May 2017, there was a large amount of downfall on this stretch, but also evidence that the Forest Service clears it frequently. This XC portion of the trail has great views and also a few spots where it is hard to follow - look for the frequent white reflectors.

After passing through a gate, you see no more ridges in front of you and the trail drops through meadows and open forests with long sight lines. The singletrack is fast, dry, and occasionally rocky here. After a quick uphill section to give your breaks a break, the trail descends more steeply into the creek bottom where it has smoother tread with a few outcrops and water bars/roots, and still decent sight lines, allowing for a screaming-fast finish. Cross the creek and pass through a gate to end up at your car.

This loop is under consideration to be proposed wilderness which could ban bikes.

Detailed Description
Bilk Mountain Loop is a 14 mile moderately popular expert route located near Helena Montana. This mountain bike only route can be used one direction and has a hard overall physical rating. This route includes 3 trails. This route climbs 3,307 ft with a max elevation of 7,210 ft then descends -3,302 ft.
Local Trail Association
Local trail association
Montana Bicycle Guild (www.montanabicycleguild.org)
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Trails in Route


  • Riding area
  • Primary Activity
    Mountain Bike
  • Difficulty rating
    Black Diamond
  • Route Type
  • Bike type
    AM, XC, CX
  • Direction
    One Direction
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More Stats for Bilk Mountain Loop mountain bike route
  • Altitude min
    4,538 ft
  • Altitude start
    4,542 ft
  • Altitude end
    4,547 ft
  • Grade max
  • Grade min
  • Distance climb
    8 miles
  • Distance down
    6 miles
  • Distance flat
    4,111 ft
Avg: 4 (1 votes)
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Recent Trail Reports Along Route

Cayuse Mountain
Sep 6, 2021 @ 4:32pm
Sep 6, 2021
Bilk Mountain
Sep 6, 2021 @ 4:30pm
Sep 6, 2021
updated closure map https://www.fs.usda.gov/Internet/FSE_DOCUMENTS/fseprd931171.pdf
Avalanche Gulch Road
May 16, 2020 @ 9:45am
May 16, 2020
Extensive deep mud. Lots of side by side traffic and campers keeping the road churned up. Recommend that this one be avoided for any kind of travel for a few weeks to dry out.
more reports »
  • By zinexo & contributors
  • #4425 - 2,165 views