Enrich your life by supporting the Great Bay 5K | Race for a Healthy Estuary!

The Great Bay 5K | Race for a Healthy Estuary will take place in-person and virtually for 2021, being held on October 30, 2021 (from October 1 – 30, 2021 for the virtual race). The 2nd Annual Great Bay 55K Challenge will also be held virtually from October 1 – 30, 2021! This unique race, which you can walk, run, use a wheelchair or treadmill to complete, allows the participant to complete a 55K during the 30 day period.

The races are a fundraiser for the non-profit Great Bay Stewards and the Great Bay National Estuarine Research Reserve, located in Greenland, NH. We offer many ways to assist with the mission of supporting the Great Bay Estuary in addition to supporting New England’s famous 5K!

One hundred percent of the net proceeds from the Great Bay 5K Race for a Healthy Estuary and 55K Challenge go toward the long-term conservation of the Great Bay estuarine system, including support for education, land protection, research, and stewardship of Great Bay. The participation and contributions of racers and walkers support the future of the estuary, while both events serve to highlight the beauty and uniqueness of Great Bay.   

Since the first running of the Great Bay 5K in October 1999, more than $300,000 has been raised in support of the Great Bay Stewards and the Great Bay National Estuarine Research Reserve.  The Great Bay 5K volunteers take great pride in presenting a race that is inclusive, family-friendly, and also a first-class event for all participants: runners, walkers and wheelchair racers; young and old; elite to casual and everyone in between.


Become a Sponsor of the Great Bay 5K and Great Bay 55K Challenge


We are accepting sponsors for the Great Bay 5K and the Great Bay 55K Challenge. Sponsorship packages start at just $100, and depending on the level a sponsor chooses, the company will receive visibility on the race website, and in press releases, social media, and/or other digital and printed media. You may also have your company banner hanging at the on-site pavilion. Send an email to find out more. 

Volunteer at the Great Bay 5K and Great Bay 55K Challenge

Whether it’s a smile to a tiring runner or an offer of a welcome beverage a the end of the race, volunteers are valued members of the Great Bay 5K team. For more details, visit the Volunteer page.

Become a Great Bay Stewards Member

Long after the Great Bay 5K race ends, the work of protecting and preserving the Great Bay continues. When you join the Great Bay Stewards, your membership makes you part of the team that works to preserve, protect, and provide education about the Great Bay, as well as help to fund a wide range of activities, and help residents and visitors learn more about this unique environment.


  • We keep you informed about new activities and programs that support the Bay.
  • Receive advance notice of special events.
  • 10% member discounts at the Great Bay Discovery Center Store.
  • Discounts on children’s programs and summer kayak trips.
Learn more about membership or to make a donation.