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Boundary Loop

Very Difficult


26.9 mile 43.3 kilometer point to point
70% Singletrack
Very Difficult


Ascent: 3,930' 1,198 m
Descent: -3,987' -1,215 m
High: 9,535' 2,906 m
Low: 6,491' 1,978 m


Avg Grade: 6% (3°)
Max Grade: 28% (15°)


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Trail shared by Chris Wandervans

Alpine heights and lakes are abundant on this ride.

Chris Wandervans

Electric Mountain Bikes Unknown

Features -none-


A classic Whitecloud loop that takes you to a high peak and overlooks lakes and jagged peaks.


This ride is a big loop in the Whiteclouds and has some substantial elevation gain and some blazing descents.

This ride begins on Boundary Creek trail. The start is a steep climb that will see you off your bike in some sections, but it is overall climbable by most people. The trail has a lot of switchbacks and can get loose during the end of the season. Settle in for the long climb and stop along the way to catch your breath and take in the views.

The trail starts in heavy trees and then becomes more open as you get towards the top, so it is best climbed in the morning if you're riding during the hot summer months. At the top of Boundary Creek you'll turn right and finish your climb to the high point. You'll have some short hiking to get to the peak. Once on the peak you'll have some expansive views and look down in the Casino Lakes.

When you are ready, drop-in on the descent. It features a steep section with large rocks to drop off and then it tapers off into some meadows. You'll then hit a four-way junction. Keep right on the Martin-Big Casino Trail. You'll now descent along alpine lakes in the shadows of peaks and trees. The trail is fast and flowing with some rocks along the descent. The trail will eventually enter a burn area on the final descent to Warm Springs Meadow. The trail becomes looser in the burn areas, but is still a blast. You'll just have to do some surfing. Once in the meadow, you'll again bear right onto the Pig Tail trail and climb to the Williams Creek Trail. Once on Williams Creek you'll have a little more climbing to the last high point.

Eventually, you'll reach the obvious high point, then you'll round a corner and down you go! It's hard not to grin on this one - the trail surface is tacky with tree cover and shade - it's one of the best descents around. It's mostly smooth, and it flows so well you'll challenge yourself not to touch the brakes except in a few tighter corners.

This is a big ride and you'll likely not see anyone until you hit Williams Creek, so be prepared and bring a water filter.


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Aug 12, 2018
Shae Mayner
Lots of hike a bike and downed trees. Fun loop. Make sure you bring water filter.

Trail Ratings

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  4.0 from 3 votes
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in Idaho


33 Views Last Month
2,822 Since Aug 5, 2015
Very Difficult



The big finale of Williams Creek.
Aug 2, 2014 near Sun Valley, ID
Aug 2, 2014 near Sun Valley, ID
The burn areas are truly unique to ride through.
Jul 5, 2017 near Sun Valley, ID
Glimpses of the big peaks.
Aug 2, 2014 near Sun Valley, ID
The meadow before the final small climb out Williams Creek
Aug 2, 2014 near Sun Valley, ID
Singletrack through the burn zone.
Jul 5, 2017 near Sun Valley, ID


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