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Boulder County

Boulder County

The best running trails in Boulder County

4.3

(55)

12,402

runners

745

runs

Running in Boulder County is one of the best ways to explore more of this region. To help you discover the most beautiful places to run, we’ve reviewed our full collection of routes in Boulder County—and are proud to present the best running trails. Click on any of the routes for more details and browse real tips and photos uploaded by other runners.

Last updated: November 6, 2025

249

runners

1. Mount Sanitas via Lion's Lair loop — Boulder Open Space and Mountain Parks

10.9km

01:45

480m

Expert run. Very good fitness required. Sure-footedness, sturdy shoes and alpine experience required.

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Expert

158

runners

2. Boulder Reservoir loop

8.50km

00:57

30m

Intermediate run. Good fitness required. Mostly paved surfaces. Suitable for all skill levels.

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Intermediate

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145

runners

3. Mount Sanitas loop via Red Rocks — Boulder Open Space and Mountain Parks

10.7km

01:39

430m

Expert run. Very good fitness required. Sure-footedness, sturdy shoes and alpine experience required.

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Expert

5.0

(3)

121

runners

4. Walker Ranch Loop trail run — Eldorado Canyon Park

12.6km

01:43

420m

430m

Expert run. Very good fitness required. Mostly paved surfaces. Suitable for all skill levels.

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Expert

118

runners

5. Mount Sanitas via Goat Path Trail loop — Boulder Open Space and Mountain Parks

6.33km

01:06

420m

Expert run. Very good fitness required. Sure-footedness, sturdy shoes and alpine experience required.

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Expert

runners

6. Doudy Draw, Spring Brook, & Greenbelt Plateau loop — Boulder Open Space and Mountain Parks

19.7km

02:21

330m

Expert run. Very good fitness required. Mostly paved surfaces. Suitable for all skill levels.

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4.0

(1)

runners

7. Green Mountain, Bear Canyon, & Mesa Trail loop — Boulder Open Space

17.7km

02:41

850m

Expert run. Very good fitness required. Mostly paved surfaces. Suitable for all skill levels.

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Expert

runners

8. McIntosh Lake loop — Longmont

5.97km

00:37

10m

Intermediate run. Good fitness required. Mostly paved surfaces. Suitable for all skill levels.

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Intermediate

3.0

(1)

runners

9. Marshall Mesa Trail Run loop — Boulder Open Space and Mountain Parks

24.4km

02:35

280m

Expert run. Very good fitness required. Mostly paved surfaces. Suitable for all skill levels.

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Expert

runners

10. High Lonesome loop — Indian Peaks Wilderness

22.5km

03:40

960m

Expert run. Very good fitness required. Sure-footedness, sturdy shoes and alpine experience required.

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Check out more Running Trails & Routes throughout Boulder County below and find the perfect route in your destination.

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The best running trails in Boulder County

1. Mount Sanitas via Lion's Lair loop — Boulder Open Space and Mountain Parks

2. Boulder Reservoir loop

3. Mount Sanitas loop via Red Rocks — Boulder Open Space and Mountain Parks

4. Walker Ranch Loop trail run — Eldorado Canyon Park

5. Mount Sanitas via Goat Path Trail loop — Boulder Open Space and Mountain Parks

6. Doudy Draw, Spring Brook, & Greenbelt Plateau loop — Boulder Open Space and Mountain Parks

7. Green Mountain, Bear Canyon, & Mesa Trail loop — Boulder Open Space

8. McIntosh Lake loop — Longmont

9. Marshall Mesa Trail Run loop — Boulder Open Space and Mountain Parks

10. High Lonesome loop — Indian Peaks Wilderness

Other adventures in Boulder County

Most popular routes in Boulder County

Most popular attractions in Boulder County

Get inspired with the komoot mobile app

Didn’t find what you were looking for?

Explore more

Get ready to conquer new peaks

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