Running Races in Thornton, Colorado 2026 | Browse All Races

Unicorn 5k (North)

Sat, Jun 20 · Thornton, CO Thornton

Road 1/2 (ish) Mile Saunter - untimed5k Run/Walk

From $16 Open Closing Soon

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Summer Sizzler- Denver

Sat, Aug 8 · Thornton, CO Thornton

Virtual 1 Mile5k10k +4

From $17 Open 5 spots left

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RMRR Fall Marathon Training Series

Sun, Aug 23 · Thornton, CO Thornton

Road RMRR Fall Marathon Training Series #1 - 10 MileRMRR Fall Marathon Training - 3 race bundle Short (10m, 20k, 10m)RMRR Fall 2023 Marathon Training Series #1 - 20 Mile +1

From $20 Closed

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RMRR September 5k/10k

Sun, Sep 13 · Thornton, CO Thornton

Road 5k10k

From $10 Open

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RMRR Fall Marathon Training Series #2

Sun, Sep 13 · Thornton, CO Thornton

Road RMRR Fall Marathon Training Series #2 - 20kmRMRR Fall Marathon Training Series #2 - 30km

From $20 Closed

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RMRR Fall Marathon Training Series #3

Sun, Sep 27 · Thornton, CO Thornton

Road RMRR Fall Marathon Training Series #3 - 10 MileRMRR Fall Marathon Training Series #3 - 20 Mile

From $20 Closed

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I Can 5k

Sat, Oct 3 · Thornton, CO Thornton

Open

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I Ain't Scared (of 5k)

Sat, Oct 31 · Thornton, CO Thornton

Road 5k

From $29 Open

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WinterFest 5k & Fun Run

Sat, Dec 12 · Thornton, CO Thornton

Road 5k Run/Walk -TIMED and ScoredFun Run/Walk (Untimed, approx .75 miles)

From $12 Open

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Running Races in Thornton, Colorado — 2026

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