Race for the Refuge

SEP
27
2026
Trail races and a six hour timed event take place on double track dirt and gravel trails at Assabet River National Wildlife Refuge in Sudbury MA. The race is cupless, aid stations are provided, and pacers are allowed for the six hour event.
Sun 27 Sep 2026
10k Trail Race 30k Trail Race 6-Hour Trail Race

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Race for the Refuge : Assabet River National Wildlife Refuge

The event is a set of trail races held at the Assabet River National Wildlife Refuge in Sudbury, MA. The course starts at the refuge visitor center and follows double track trails of dirt and gravel that pass ponds, pine and oak forest, and former military bunkers.

Distances and formats include:

  • 10K one loop
  • 30K three loops
  • 6 hour timed event with multiple loops allowed

The six hour event is scored by the most loops completed and then by shortest time. Runners in the six hour event must begin their final lap by 2:00 PM and finish that lap by 3:00 PM for it to count. Pacers are permitted only for the six hour event; pacers must register and check in to obtain a pacer bib, may start at noon or later, may accompany one runner at a time, and cannot carry a runner or supplies for them. Pacers may use aid stations at no cost.

There are two aid stations on the loop, including a main station at the start and a halfway station at Taylor Road. Stations provide water, hydration mix, pretzels, orange slices, banana halves, Swedish fish, cola, and ginger ale. This is a cupless race; participants must carry and pack out any personal fuel or waste. Dogs are not permitted on refuge lands and children must be supervised. All entrants receive registration swag and top finishers in each event receive prizes. Proceeds support nature education, trail improvements, refuge sites in Massachusetts, a volunteer coordinator, and local charities. Visit the organization's website for the most recent information.

30 km
30k Trail Race
10 km
10k Trail Race
6-Hour Trail Race
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