Running Races in Thornton, Colorado — 2026

There are 9 running races in Thornton, Colorado in 2026. The next is the Summer Sizzler- Denver on August 8. Distances include 5K races, half marathons, ultras.

RMRR Fall Marathon Training Series

Sun, Aug 30 · Thornton, CO Thornton
Road RMRR Fall Marathon Training - 3 race bundle Short (10m, 20k, 10m)RMRR Fall Marathon Training Series #1 - 10 MileRMRR Fall 2023 Marathon Training Series #1 - 20 Mile +1
From $20 Open
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Unicorn 5k (North)

Sat, Jun 19 · Thornton, CO Thornton
Road 1/2 (ish) Mile Saunter - untimed1/2 (ish) Mile Saunter - untimed5k Run/Walk +1
From $16 Open Closing Soon
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All Colorado Races

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