4K Trail Run

Set sail for a truly unique running experience at the 4K Trail Run on Cathleen Stone Island, taking place on May 20, 2026, in Boston, MA. This isn't your average city race; participants will embark on a scenic 30-minute ferry ride to Cathleen Stone Island in the Boston Harbor, where the 4K trail adventure unfolds. Known as "the most unique race in Boston," the event offers a captivating backdrop and a chance to explore one of the most beautiful spots in the harbor.

Beyond the picturesque course, which winds through the island's trails, this race is celebrated for its vibrant atmosphere and philanthropic heart. For 25 years, the 4K Trail Run has served as Cathleen Stone Island Outward Bound's annual fundraiser, directly supporting free, hands-on science learning and social-emotional development for Boston's youth. Runners consistently praise the event as "a run with a view, a purpose, and a whole lot of heart," highlighting the post-race celebration that includes dinner, beer, and an on-island party—creating an unforgettable afternoon and evening for individuals and corporate teams alike.

With typical race day conditions seeing highs around 68F and lows around 52F, and only a 15% chance of precipitation, May 2026 promises ideal weather for an exhilarating trail run. The journey begins with check-in at either Long Wharf or EDIC Pier before the ferry transports runners to the island, setting the stage for a memorable race and celebration.