Running Races in Thornton, Colorado 2026 | Browse All Races

There are 8 running races in Thornton, Colorado in 2026. The next is the RMRR Spring Marathon Training Series #2 on April 11. Distances include 5K races, 10K races.

RMRR Spring Marathon Training Series #2

Sat, Apr 11 · Thornton, CO Thornton

Road MTS#2 - 10 MileMTS#2 - 20 Mile

From $20 Open Closing Soon

Treat Trot - Denver

Sat, Jun 13 · Thornton, CO Thornton

Virtual 5K10K15K +4

From $17 Open Closing Soon

Unicorn 5k (North)

Sat, Jun 20 · Thornton, CO Thornton

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

From $16 Open

Summer Sizzler- Denver

Sat, Aug 8 · Thornton, CO Thornton

Virtual 1 Mile5k10k +4

From $17 Open 5 spots left

RMRR September Trophy Series

Sun, Sep 13 · Thornton, CO Thornton

Road 5k10k

From $10 Open

I Can 5k

Sat, Oct 3 · Thornton, CO Thornton

Open

I Ain't Scared (of 5k)

Sat, Oct 31 · Thornton, CO Thornton

Road 5k

From $29 Open

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

Running Races in Thornton, Colorado — 2026

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