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River of No Return Endurance Runs 50k



31.2 mile 50.1 kilometer loop
84% Runnable


Ascent: 6,084' 1,855 m
Descent: -6,085' -1,855 m
High: 8,418' 2,566 m
Low: 5,011' 1,527 m


Avg Grade: 7% (4°)
Max Grade: 30% (17°)


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Trail shared by Jeff Fullmer


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River of No Return (RONR) Endurance Runs offer runners a unique opportunity to experience Idaho's remote beauty.

Jeff Fullmer

Features River/Creek · Views · Wildflowers · Wildlife

Stay on course and beat the cutoffs, which are very generous. Cutoffs for the 50K are 6 hours to Bayhorse (12:30 pm) and a 12 hour cutoff at the Finish.


With a start and finish in Challis, Idaho, the River of No Return (RONR) Endurance Runs offer runners a unique opportunity to experience Idaho's remote beauty. Choose between distances of 25k, 50k, or 108k, where you'll be challenged by varying terrain and awed by gorgeous scenery. Cradled by the Salmon River to the south and the Frank Church Wilderness to the north, the RONR Endurance Runs provide participants the chance to see – among other sights – the Blue Mountain, the Lombard Trail, Bayhorse Lake, and Buster Lake.

(Mapping provided via tracking from a Garmin Forerunner during the 2016 50k -Jeff Fullmer: Idaho Falls Trail Runners. Written summaries and course content obtained via the website.)

Need to Know

After the Keystone aid station as you run down to Bayhorse there are several points to dip your hat or wash your hands in the stream that meanders next to and across the trail. A heavy snowpack year will mean the possibility of wet shoes.

Runner Notes

This 50k is all about long stretches, either long uphills or long downhills. This can easily lead to muscle fatigue and cramping as your muscles transition after several miles to either a new pace/gait uphill or downhill. If it is warm this increases the likelihood of cramps. The trail is mostly 4 wheeler tracks so expect larger rocks and debris during certain portions, especially when you leave Keystone for the 2nd time and head down to the Custer Motorway on the logging road. A shoe with good cushion is recommended.


After leaving the START at the Challis City Park, you'll head south on the HWY 93 shoulder for several hundred yards until reaching the 4-wheeler trail next to the highway on the right. Follow the two track trail down for two miles to the Land of the Yankee Fork Interpretive Center. Cut through the parking lot and begin the Lombard Trail System, a two track trail that will lead you for quite some time. Stay on the Lombard Trail for a 4 mile climb, and up to a lower saddle where an informational placard will give you some geographic history of the surrounding area. Continue ~1.5 miles on the Lombard Trail (now cutting along Blue Mountain, side-hill) to the first Aid Station, BIRCH CREEK SADDLE.

From BIRCH CREEK SADDLE, you'll continue on the Lombard Trail and head up a tough climb before reaching another placard which describes the Bighorn Sheep in the area and their habitat. You wanted some views? Well here they are: The Salmon River below you, the Twin Peaks and the River of No Return Wilderness off to your right, Mt. Borah (Idaho's tallest peak at 12,662') off to the south skyline, and some wild, wild country ahead of you in the Salmon-Challis National Forest. The Lombard Trail climbs up to 8300' now before descending sharply to an intersection where the aid station known as KEYSTONE will greet you. If you haven't seen a deer, elk, antelope, sheep, bear, wolf, hawk or eagle by now then you hopefully registered under the Legally Blind category for the race.

From the intersection at KEYSTONE, pick up Road 052 (go left-south) and ascend briefly to a summit before a 3.5 mile downhill cruise to the mining Ghost Town, BAYHORSE. You'll pass by the abandoned Pacific Mine, outbuildings and rail car transport structures on your adventure to BAYHORSE. Watch for a fabled old miner in these parts, named Choppy. If you think you see him, run faster. As you approach BAYHORSE past the old hillside mill, your crew can watch for you on the hillside coming down to the aid station.

Back up for 4 miles the way you came down. Now you can see just where you stand against the competition.

Leaving KEYSTONE, now to the north, a 3.5 mile descent down the 4WD road (RD 052) will offer some spectacular views and tie you into Garden Creek and the Garden Creek Road (RD 069). Continuing down Garden Creek Road for ~2 miles takes you to the tie-in of the CUSTER MOTORWAY and the aid station.

Departing the final aid station at the CUSTER MOTORWAY, you'll take off on the final, well-sloped downhill on a paved road which will lead you along Garden Creek, down Main Street Challis, and back to the FINISH at the Challis City Park.

Flora & Fauna

Sagebrush, wildflowers, and pine trees are abundant.

History & Background

A small town with a big heart, Challis, Idaho is the ideal base camp for Idaho's premier trail races. Challis is located in the center of Idaho surrounded by recreation on public lands in the White Cloud Mountains, Frank Church River of No Return Wilderness, and Salmon-Challis National Forest.

If you want to make a vacation out of your race weekend, you'll find unparalleled fishing, hiking, mountain biking, rockhounding, wildlife viewing, mountaineering, river rafting, hunting, and off-highway trail riding. If you're a history buff, you'll be busy for days at the Land of the Yankee Fork Park, North Custer Museum, ghost towns of Custer, Bonanza, Bayhorse and the behemoth gold dredge on the Yankee Fork. Get off the beaten track and trace the trail where wagons carried food and necessary supplies from Challis to the Yankee Fork Mining District by driving the scenic Custer Motorway. Explore Challis by starting a downtown walking tour at the North Custer Museum.

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in Challis


  4.0 from 2 votes
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9 Views Last Month
633 Since May 25, 2017



Don't forget to periodically look up! This can tend to be one of the warmest parts of the 50k course.
Jun 26, 2017 near Challis, ID
All of the climbing serves up views for days!
May 25, 2017 near Challis, ID
A sight for sore eyes as you get a glimpse of the Bayhorse Townsite aid station coming in at mile 16.
Jun 26, 2017 near Challis, ID
Wildflowers, high wind swept ridges and clouds to guide you along your way.
May 25, 2017 near Challis, ID
The logging road on the way to the Custer Motorway. It is all downhill but those with minimalist shoes will get beat up by the rocks. If your quads are ok, they won't be soon!
Jun 27, 2017 near Challis, ID
Starting line (Actually taken during the start of the 108K) It is light at the 50k start.
May 25, 2017 near Challis, ID