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Big-Little Boulder Loop



22.4 mile 36.0 kilometer loop
80% Singletrack


Ascent: 3,466' 1,056 m
Descent: -3,500' -1,067 m
High: 9,560' 2,914 m
Low: 6,102' 1,860 m


Avg Grade: 6% (3°)
Max Grade: 27% (15°)


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Trail shared by Chris Wandervans

Climb in the jagged peaks and alpine lakes.

Chris Wandervans

Electric Mountain Bikes Allowed

Features -none-


This is a classic ride that will take you high up into the alpine environments of the Whitecloud mountains. The climbing is long, but never grueling and the downhill is sublime. This is a big backcountry ride so it is best to come prepared for any and all issues.

Need to Know

Bring a water filter. There is an out house at Frog Lake.


This ride starts at the junction with the Livingston Mill Rd. and the East Fork Rd. There is a parking area at the junction or you can proceed down the road to a larger parking lot.

The trail begins right near the Livingston Mill and meanders along the creek before turning sharply up the hill. There are a couple short and steep uphills, but these do not last long. You'll cross the creek and then the trail will mellow out. From this point, the trail gradually switchbacks all the way to the pass. There is a nice lake along the way to stop for a snack.

You'll pass smaller and smaller trees as you reach the pass and the views will become ever more scenic. Once at the pass, you'll have a short and fast descent to Frog Lake. This lake is one of the most amazing lakes in the White clouds and has jagged peaks as a backdrop. From this point, the trail descends further and becomes more rocky and challenging.

Starting from an intersection with Livingston Mill-Castle Divide, head downstream, following Little Boulder Creek. The upper reaches of the trail are mostly through the trees over fun and challenging terrain. Although there are plenty of rocks and roots, the trail is very rideable. You'll encounter few big meadows along the way before getting to the lower reaches that hug the hillside side just above Little Boulder Creek.

The route climbs briefly as it moves away from Little Boulder Creek over to the East Fork valley.

The finale of the route is a rowdy descent on dry sage hillsides. As you point your wheel down the last hill into the East Fork of the Salmon River, you'll be treated to downriver views of the Whitecloud Mountains.


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Jul 31, 2017
Paul Lindfield
24mi — 5h 54m
Oct 1, 2016
Daniel Green
Sep 26, 2016
Nicholas Ryan
Jul 24, 2016
Doug Jenkins
3h 00m
Jul 4, 2016
Gee Toe
5h 45m
Jul 2, 2016
Kevin Matluk
Trail was in great condition, Started and ended at the bottom of the dirt road. Suggest bringing a fly rod, I caught a couple trout in frog lake 22.4mi

Trail Ratings

  4.7 from 9 votes


  4.7 from 9 votes
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in Idaho


29 Views Last Month
4,159 Since Aug 11, 2015



The last bit of the Castle Divide route is through open sage meadows.
Jul 27, 2014 near Sun Valley, ID
Frog Lake early in the morning.
May 15, 2015 near Sun Valley, ID
Nice bridge riding
May 15, 2015 near Sun Valley, ID
Taking a break from the climb
May 15, 2015 near Sun Valley, ID
Down into Frog Lake
May 15, 2015 near Sun Valley, ID

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