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A wide sandstone canyon under a blue sky at Colorado National Monument, near Fruita
Rebecca Carr / Unsplash

Desert RATS 100K, 50K, 21K and 10K: courses and aid stations

Four races from Mack Ridge, west of Fruita, from a 5.9 mile lollipop to a 63.5 mile out and back to the Western Rim.

April 9 to 11, 2027 Fruita, Colorado

Desert RATS is a UTMB World Series event in April, based in Fruita in western Colorado. All four races start and finish at Hawkeye Trailhead, just off the Mack exit of I-70, and begin on the Kokopelli Loops of Mack Ridge, singletrack the BLM manages as part of McInnis Canyons National Conservation Area. The 100K keeps going west on the Kokopelli Trail to Rabbit Valley and a loop of the Western Rim, with the Colorado River below.

The map shows the 2026 courses and aid stations. The 2027 race pages still carry them, and the organizer says the route can change with permitting.

Out here the organizer warns of limited cell and satellite connectivity, and tracking splits can run up to two hours late. Download the course map before race day, since your phone's GPS will still put you on it with no signal.

This is an unofficial guide: Goat Maps isn't affiliated with Desert RATS Trail Running Festival by UTMB. Check the official site before you enter or race.

Desert RATS course map

Every course's aid stations on the Goat Maps topo map. Each course has a map of its own further down.

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Save it in Goat Maps for a recce or race day. GPS shows where you are even without a signal.

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Desert RATS courses

CourseDistanceClimbingStartTime limit
100K63.5 mi (102 km)6,632 ft (2,021 m)Sat, Apr 10, 5:00 AM20 h
50K30.7 mi (49 km)3,385 ft (1,032 m)Sat, Apr 10, 7:00 AM10 h
21K13 mi (21 km)1,678 ft (512 m)Sun, Apr 11, 8:30 AM5 h
10K5.9 mi (10 km)604 ft (184 m)3 h

Desert RATS 100K

A lap of Mack Ridge, then out the Kokopelli Trail to the Western Rim and back.

Distance
63.5 mi (102 km)
Climbing
6,632 ft (2,021 m)
Start
Sat, Apr 10, 5:00 AM
Time limit
20 h

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As far as Crossroads, mile 17.6, this is the 50K course: a mile of dirt road, then singletrack where passing is hard, so settle into your spot early. You run Rustler's Loop clockwise between two visits to Rustler's, then climb to Pizza Overlook with the Colorado River in view and follow the rim in and out of the canyons.

After Crossroads comes the remote, rolling Troybuilt Trail, 7.3 miles with no aid, so carry water. You drop to Salt Creek, climb hard to the aid station and take a frontage road to Rabbit Valley, where your crew and drop bag wait and you have to be out by 3:00 PM. From Western Rim you loop past an unstaffed water drop and back to the same station, and the climb off the rim is a tough one. Then it's Rabbit Valley and Salt Creek again, a wash and a last mile of gravel to the finish.

aid stations

miWhereCutoff
0Hawkeye Trailhead (start and finish)
6.2Rustler's Crew
9.8Rustler's Crew
13.7Pizza Overlook
17.6Crossroads
24.9Salt Creek
32.5Rabbit Valley Crew, Drop bagSat 3:00 PM
37.4Western Rim Sat 4:30 PM
44.7Water Drop (unstaffed water)
46.4Western Rim Sat 8:00 PM
51.2Rabbit Valley Crew, Drop bagSat 9:15 PM
58.8Salt Creek Sun 12:00 AM
63.5Hawkeye Trailhead (start and finish) Sun 1:00 AM
Layered red sandstone cliffs over a scrubby canyon at Colorado National Monument
Drew Bernard / Unsplash

Desert RATS 50K

The Kokopelli Loops on Mack Ridge, with a bonus lap of Rustler's Loop.

Distance
30.7 mi (49 km)
Climbing
3,385 ft (1,032 m)
Start
Sat, Apr 10, 7:00 AM
Time limit
10 h

Take this course offline

Download its map in Goat Maps and you can find the next aid station without a signal.

Open in web map

The 50K shares its first 17.6 miles with the 100K: in to Rustler's, a lap of Rustler's Loop and back to Rustler's, then Pizza Overlook and the rim above the river to Crossroads, where the cutoff is noon.

From there the Troybuilt Trail brings you to the Troybuilt aid station, 6.5 miles on. Leaving it you face the steep, hot climb of the day up to Mack Ridge, close to the edge of the overlook, before a new stretch of singletrack drops 2.8 miles to the back of the parking lot and the finish.

aid stations

miWhereCutoff
0Hawkeye Trailhead (start and finish)
6.2Rustler's Crew
9.8Rustler's Crew
13.7Pizza Overlook
17.6Crossroads Sat 12:00 PM
24.2Troybuilt Crew
30.7Hawkeye Trailhead (start and finish) Sat 5:00 PM
Red sandstone fins and spires above a canyon at Colorado National Monument, near Fruita
Drew Bernard / Unsplash

Desert RATS 21K

A loop past Pizza Overlook and Moore Fun, with the longer races' rim views.

Distance
13 mi (21 km)
Climbing
1,678 ft (512 m)
Start
Sun, Apr 11, 8:30 AM
Time limit
5 h

Take this course offline

Download its map in Goat Maps and you can find the next aid station without a signal.

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You head out a mile of dirt road and down a steep hill to Crossroads, then follow the rim in and out of the canyons and climb a steep, ledgy section to Pizza Overlook. The descent after it is rugged and longer than it looks.

Moore Fun comes at mile 7.1, with an 11:00 AM cutoff. The trail from there gets rocky and technical on a big climb, then drops to a cattle guard, and you take the same dirt road back to the finish. The organizer says Active named it one of the most scenic half marathons.

Desert RATS 10K

A lollipop on Steve's Loop, over narrow canyons and the Colorado River.

Distance
5.9 mi (10 km)
Climbing
604 ft (184 m)
Time limit
3 h

Take this course offline

Download its map in Goat Maps and you can find the next aid station without a signal.

Open in web map

The 10K goes down the same dirt road and steep hill to Crossroads, runs the rim and a steep, ledgy climb to Pizza Overlook, and comes back through Crossroads for a second stop. The last push is up the hill to the cattle guard and a mile of dirt road to the finish.

In 2026 it ran on Friday evening. In 2027 it moves to Sunday, and its start time wasn't out when this page was checked.

Registration and fees

Registration for 2027 is open online. When this page was checked the 100K cost $295, the 50K $185.69, the 21K $151.37 and the 10K $69.63, each plus a processing fee ($29.50 on the 100K). The organizer says prices can go up at any time. Online entry closes Sunday, April 4, 2027 at 11:59 pm PT, or earlier if a race sells out. There's no waitlist. You can sign up at the expo for any distance still open, but not on race day.

Entries can't be refunded or transferred. You get one deferral to the next year for any reason if you ask by March 11, 2027. You must be 18 for the 100K and 50K, 16 for the 21K and 12 for the 10K.

Getting to Fruita and the start

A round metal shed on farmland near Fruita, with snow-streaked cliffs behind
Madeline Barbera / Unsplash

Fruita is 15 miles from Grand Junction, whose airport has nonstop flights from Denver, Salt Lake City, Las Vegas and Phoenix among others. Grand Junction lies 247 miles west-southwest of downtown Denver. The expo and bib pick-up are in Civic Center Park in downtown Fruita.

In 2026 runners parked in a new lot at 1065 US-6 & 50 in Mack and walked half a mile to Hawkeye Trailhead, about 20 minutes. There was no bus from the high school any more, no drop-off at the trailhead, and no camping in the lot: a runner whose crew camps there is disqualified. For camping, the organizer points to James M. Robb State Park, Rabbit Valley and the North Fruita Desert at 18 Road. Check the 2027 runner guide when it's out.

Crewing, pacers and drop bags

Only the 100K and 50K allow crews, and only at their crew stations. For the 100K that's Rustler's and Rabbit Valley; for the 50K, Rustler's and Troybuilt. You can't park at Rustler's or Troybuilt: in 2026 crews rode shuttles from the start and finish line, and the 100K shuttle to Rustler's ran until 4 PM. Rabbit Valley is a drive, off I-70 at Exit 2 and south to the parking area, then a quarter mile on foot.

There are no pacers: the race rules allow them only at events with a 100 mile distance. 100K runners can send a drop bag to Rabbit Valley, which they pass twice. It has to fit through an 8 by 10 inch opening and be no longer than 16 inches.

Weather and what to carry

Snow on sandstone towers and evergreens at Colorado National Monument
Intricate Explorer / Unsplash

April at Grand Junction's airport averages a high of 66°F and a low of 38°F, on the 1991 to 2020 normals. The organizer warns it can be anything from hot to snowy that time of year, and that it can snow on I-70 in April, so leave time for the drive.

The 100K starts at 5 AM and its finish cutoff is 1 AM, and a headlamp with spare batteries is on its mandatory kit list, along with a running pack, a phone, 1 liter of water, a cup, a food reserve, a hooded jacket, a hat, a whistle and a survival blanket. The organizer suggests at least 200 lumens for the headlamp and 800 kcal of food. The 50K list is shorter. Every distance needs a cup, since aid stations have none, and trekking poles are allowed.

Desert RATS aid stations and GPS coordinates

For crews and spectators: each place on the map in decimal degrees, latitude first. Paste them into any map app or add them as waypoints in Goat Maps.

  • Hawkeye Trailhead (start and finish)

    4,682 ft (1,427 m)

    39.21121, -108.87110

  • Rustler's

    4,547 ft (1,386 m)

    39.17346, -108.82971

  • Pizza Overlook

    4,770 ft (1,454 m)

    39.18611, -108.87232

  • Crossroads

    4,724 ft (1,440 m)

    39.19515, -108.86491

  • Salt Creek

    4,915 ft (1,498 m)

    39.22273, -108.91299

  • Rabbit Valley

    4,642 ft (1,415 m)

    39.18469, -109.01722

  • Western Rim

    4,872 ft (1,485 m)

    39.13778, -109.05886

  • Water Drop (unstaffed water)

    4,629 ft (1,411 m)

    39.13283, -109.07607

  • Troybuilt

    4,623 ft (1,409 m)

    39.21902, -108.88403

  • Moore Fun

    4,593 ft (1,400 m)

    39.17689, -108.83115

Desert RATS FAQ

When is Desert RATS 2027?

April 9 to 11, 2027. The 100K starts at 5:00 AM and the 50K at 7:00 AM on Saturday, April 10. The 21K and 10K run on Sunday, April 11: the 21K race page gives an 8:30 AM start, and the 10K start time is still to be announced.

Is Desert RATS a Western States qualifier?

The 100K is. Finishing the 2026 race in 18 hours counted toward the 2027 Western States lottery, and the April 2027 race is on the list for the 2028 lottery with the same 18 hours. That's two hours inside the race's own 20 hour limit. The 50K, 21K and 10K don't qualify.

How many Running Stones do you get at Desert RATS?

3 for the 100K, 2 for the 50K and 1 for the 21K. The 10K gives none. The top three women and men in the 100K and 50K also win a place at the UTMB World Series Finals in the same category, CCC or OCC, and pay for that bib.

Can you have a pacer at Desert RATS?

No. The race rules allow pacers only at events with a 100 mile distance, and Desert RATS tops out at 100K.

How long is the Desert RATS 100K?

The 2026 aid station chart puts it at 63.5 miles with 6,632 feet of climbing, a little over the 100 km its name says. The chart's figures come from CalTopo, and the organizer warns your watch may read up to a mile either way.

Is there cell service on the Desert RATS course?

Not much. The organizer warns of limited cellular and satellite connectivity, and LiveTrail splits, which are timing checks and not GPS tracking, can lag up to two hours. You still have to carry a phone at every distance. Download the course map in Goat Maps before you go: your phone's GPS works without a signal.

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Updated . An unofficial guide, from the organizer's published information. Coordinates from the organizer's course and OpenStreetMap contributors. Photos from Unsplash. Organize a race? We help with course files.