Marathon Races in Colorado

Find upcoming marathon races in Colorado — with dates, locations, and direct registration links.

97 upcoming marathon races found in Colorado

Upcoming Marathon Races in Colorado

5K Registration+5

Aug 15

Bagel Run 5K/10K/13.1 DENVER/AURORA

Sat, August 15, 2026

Centennial, CO

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Marathon

Aug 15

Boulder Rez Marathon

Sat, August 15, 2026

Boulder, CO

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5K Registration+5

Aug 15

Run for PB& J 5K/10K/13.1 DENVER/AURORA

Sat, August 15, 2026

Centennial, CO

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Half Marathon+2

Aug 15

Endurance Race Series – Westminster 13.1 , 10K, 5K

Sat, August 15, 2026

Westminster, CO

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Half Marathon

Aug 15

Mount Sneffels Marathon & Half Marathon

Sat, August 15, 2026

Ouray, CO

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Half Marathon+1

Aug 16

Erie Half & 5k

Sun, August 16, 2026

Erie, CO

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Half Marathon

Aug 22

Arrowhead Half Marathon

Sat, August 22, 2026

Edwards, CO

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Staunton Rocks! Marathon+1

Aug 22

Staunton Rocks! Marathon and Half Marathon

Sat, August 22, 2026

Pine, CO

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Half Marathon+1

Aug 22

Byers Peak Stampede Half Marathon & 5K Run

Sat, August 22, 2026

Fraser, CO

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Half Marathon+2

Aug 23

Pioneer Prairie Dog Half, 10k & 5k

Sun, August 23, 2026

Westminster, CO

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RMRR Fall Marathon Training - 3 race bundle Short (10m, 20k, 10m)+3

Aug 23

RMRR Fall Marathon Training Series

Sun, August 23, 2026

Thornton, CO

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5K Registration+5

Aug 29

Run to Breast Cancer 5K/10K/13.1 DENVER/AURORA

Sat, August 29, 2026

Centennial, CO

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5K Registration+5

Aug 29

Sloth Run 5K/10K/13.1 DENVER/AURORA

Sat, August 29, 2026

Centennial, CO

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RMRR Fall Marathon Training - 3 race bundle Short (10m, 20k, 10m)+3

Aug 30

RMRR Fall Marathon Training Series

Sun, August 30, 2026

Thornton, CO

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Kid's Dash+6

Sep 5

Golden Harvest Half Marathon & 5k/10k - Denver

Sat, September 5, 2026

Denver, CO

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5k+6

Sep 6

Golden Harvest Half Marathon & 5k/10k - Colorado Springs

Sun, September 6, 2026

Colorado Springs, CO

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Half Marathon+3

Sep 7

Labor Day Half Marathon

Mon, September 7, 2026

Parker, CO

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Black Squirrel Half Marathon

Sep 12

Black Squirrel Half Marathon

Sat, September 12, 2026

Bellvue, CO

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Trail Sisters Women's Half Marathon+1

Sep 12

Trail Sisters Women's Half Marathon & 10k

Sat, September 12, 2026

Buena Vista, CO

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5K Registration+5

Sep 12

Run for Mental Health 5K/10K/13.1 DENVER/AURORA

Sat, September 12, 2026

Centennial, CO

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5K Registration+5

Sep 12

National Chocolate Day: Run for Chocolates 5K/10K/13.1 DENVER/AURORA

Sat, September 12, 2026

Centennial, CO

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RMRR Fall Marathon Training Series #2 - 20km+1

Sep 13

RMRR Fall Marathon Training Series #2

Sun, September 13, 2026

Thornton, CO

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Half Marathon+3

Sep 19

Autumn Run

Sat, September 19, 2026

Buena Vista, CO

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Half-Marathon+5

Sep 19

Beulah Challenge and OverIt Series

Sat, September 19, 2026

Beulah, CO

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Half Marathon+5

Sep 19

All-Out Fall Fest

Sat, September 19, 2026

Westminster, CO

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Marathon+3

Sep 20

Pikes Peak Marathon

Sun, September 20, 2026

Manitou Springs, CO

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Half Marathon+3

Sep 20

Fall Equinox

Sun, September 20, 2026

Fort Collins, CO

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Red Feather Trail Jamboree 50 Mile+3

Sep 25

Red Feather Trail Jamboree

Fri, September 25, 2026

Red Feather Lakes, CO

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50k Bike+3

Sep 26

Estes Epic

Sat, September 26, 2026

Estes Park, CO

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5K Registration+5

Sep 26

Oktoberfest Run 5K/10K/13.1 DENVER/AURORA

Sat, September 26, 2026

Centennial, CO

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