Trail Run Project Logo

Tour the old mining towns of the San Juan Mountains at this scenic mountain marathon.

Your Rating:      Clear Rating
Your Difficulty:
Your Favorites: Add To-Do · Your List
Zoom in to see details
Map Key







12,908' 3,934 m


9,323' 2,842 m


4,353' 1,327 m


4,353' 1,327 m



Avg Grade (3°)


Max Grade (14°)

Dogs No Dogs

Features Lake · River/Creek · Views · Wildflowers · Wildlife


This epic 50K ultramarathon and 26.7 marathon follows the "Alpine Loop" mining road counter-clockwise linking historic mining ghost towns, Howardsville, Eureka, Animas Forks & Gladstone. The high point is 12,930 feet atop California Pass. The low point is Silverton at 9,318 feet. Total vertical gain is 3,800 feet for the marathon and 4,400 feet for the 50K. The 50K runners will complete an out-and-back to Niagara Gulch before joining the marathon course.

Need to Know

This is an open jeep road that sees ATV and Jeep traffic during this time in the summer. Please prepare with bandanas or headwraps to cut down on any dust in the air.

Runner Notes

Weather is often unpredictable during the summer monsoon season. Expect afternoon showers during the summer and watch for lighting.


Along the course you are introduced to the rugged mining landscapes of southwest Colorado. Expect scenic mountain views, rivers, wildflowers, and one very BIG climb to the top of California Pass!

50 Kilometer: Before joining the marathon course, head out of Memorial Park up Highway 110 towards Niagara Gulch and Gladstone. Run 2.3 miles to the turnaround point at the Niagara Gulch checkpoint/water stop and return to Memorial Park for aid and then join the marathon course:

Marathon: Leaving Memorial Park, follow 18th Street to Cement Street, turning left and then running through Silver Lakes campground. Proceed straight on this road until you intersect asphalt road (County Road 2). Turn right on CR 2. Follow asphalt road for approximately 0.75 mile.

Howardsville: (4 miles; +380 feet cumulative climb; overall this section is fairly flat and fast with minimal rocky footing). At the base of the big asphalt climb, 100 yards after the red brick “Powerhouse” on right side of the road, turn right onto narrow bumpy gravel road. DO NOT follow the asphalt road up the climb. Go straight on rocky gravel road that runs alongside the Animas River for approximately 2.5 miles to Howardsville aid station.

**NOTE: There is one minor stream crossing as part of this section. You may be able to cross the stream without getting wet feet…or you may not. At this point, you are allowed to go left off course and climb up above the big metal pipe out of which the stream water flows. It is up to each runner to decide how to proceed. Look for the Howardsville aid station before you intersect the big gravel road at mile 4.

Eureka: (7.6 miles; +600 feet cumulative climb; overall this section is flat and fast with smooth gravel footing). After Howardsville aid station continue straight on County Road 2 Follow the main road 3.6 miles to Eureka aid station. Look for aid station on left side of road, shortly after crossing the bridge over Animas River before starting big climb.

Animas Forks (11 miles; +1,800 feet cumulative climb; this section is the beginning of the race’s big climb, there are few flat spots). Proceed straight up on this rocky jeep road. A half mile before Animas Forks aid station, road forks. Go LEFT!! DO NOT follow road to Engineer and Cinnamon Pass. Look for aid station somewhere in old abandoned town-site of Animas Forks.

California Pass (12,960ft) (16 miles; +3,560 feet cumulative climb; this is the big climb; steep grades near top of climb; watch for sheep in upper valley). Proceed straight on this even rockier jeep road. Take the right fork at the Placer Gulch intersection. Look for the aid station at the very top of California Pass.

Gladstone (19.8 miles; steep rocky downhill section). After the California aid station proceed down rocky gravel road approximately 0.75 mile. Take the left fork at Poughkeepsie Gulch intersection. Follow sign that reads “Silverton”. Climb about 400 feet to the top of Hurricane Pass (12,400 feet). Follow the rocky road down steep hill. At Corkscrew Gulch intersection take the left fork continuing downhill. Keep going straight down hill to Gladstone aid station. Look for aid station on left side of road about 100 yards after intersection with wide gravel road.

Niagara Gulch (24 miles; smooth gravel road; fastest section). Proceed straight on wide gravel road (CR 110). Approximately 0.75 mile past Silverton Mountain Ski Area (on your left), at base of short steep hill, make an easy right turn onto narrow rocky road, shortly after which will be a very minor (if at all) stream crossing (there is no way to circumnavigate this stream crossing). After following the rocky road for 0.9 miles you'll be lead back onto main wide gravel road. Follow this road to Niagara Gulch aid station, on right side of road, about 2 miles from finish line.

Finish: The last 0.75 mile is asphalt road with some shoulder. Run through the grassy field at Memorial Park to the finish line. Congratulations!

Flora & Fauna

Wildflowers including columbines.


Shared By:

Jubilee Paige

Trail Ratings

  5.0 from 2 votes


in Silverton


  5.0 from 2 votes
5 Star
4 Star
3 Star
2 Star
1 Star
Recommended Route Rankings


in Silverton


in Colorado


15 Views Last Month
4,689 Since Jul 24, 2018



Mountain Marathon of the San Juans!
Jul 24, 2018 near Silverton, CO


Current Trail Conditions

Add Your Check-In


Jul 9, 2020
Jubilee Paige
Jul 28, 2018
Lost in Alaska