Thompson Island Outward Bound 4K Trail Run

Embark on an unforgettable adventure at the Thompson Island Outward Bound 4K Trail Run on May 21, 2026, in Boston, Massachusetts. This truly unique event begins with a scenic 30-minute ferry ride across Boston Harbor to Cathleen Stone Island, formerly Thompson Island, setting the stage for an extraordinary trail running experience. Runners will traverse 204 acres of diverse terrain, including rolling hills, forests, meadows, salt marshes, and beaches, offering breathtaking views and a challenging course of rocks, gravel, and unstable surfaces.

Known as the most unique race in Boston, this 4K trail run is celebrated for its distinctive island setting and its impactful mission. Beyond the invigorating run, participants are treated to a vibrant post-race celebration, complete with a full BBQ dinner and refreshing Harpoon beer, fostering a fantastic atmosphere for individual runners and corporate teams alike. Typical race day conditions in late May offer comfortable highs around 69F and lows around 53F, with only a 15% chance of precipitation, providing ideal weather for exploring the island's natural beauty. Your participation directly supports Cathleen Stone Island Outward Bound's mission to deliver free, hands-on science learning and social-emotional development to Boston's youth, making every stride count towards a greater cause.