4K Trail Run
About this race
The 4K Trail Run is the most unique race in Boston! Taking place on Cathleen Stone Island in the Boston Harbor, teams and individual runners will enjoy an afternoon and evening with their coworkers and friends. After a short ferry ride (~30 minutes) to the island, the event will kick off with a 4K race around the island and end with dinner, beer, and an on-island party.
Every dollar raised from the 4K Trail Run supports Cathleen Stone Island's mission to deliver free, hands-on science learning to Boston's youth. The 4K Trail Run is an excellent way to invest in education of Boston youth and is our most popular corporate fundraising event. This year’s 4K Trail Run will take place on Wednesday, May 20th, and Thursday, May 21st, 2026 (Teams and runners must select one day to participate).
Pick your distance
Running
Wednesday 4K Trail Run - Individual Registrations
Each runner receives chip-timed entry, round-trip ferry transportation, a race t-shirt, dinner and beer!
Wednesday 4K Trail Run - Team Registrations
Each runner receives chip-timed entry, round-trip ferry transportation, a race t-shirt, dinner and beer!
Thursday 4K Trail Run - Individual Registrations
Each runner receives chip-timed entry, round-trip ferry transportation, a race t-shirt, dinner and beer!
Thursday 4K Trail Run - Team Registrations
Each runner receives chip-timed entry, round-trip ferry transportation, a race t-shirt, dinner and beer!
Typical race-day weather
Based on 11 years of historical conditions on this event's race dates in Boston.
Course
Route map and elevation profile
No course map published yet.
The organizer hasn't released a route for this event, and we don't publish guesses. If you're the organizer, send us a GPX file and we'll draw the profile.
Reviews
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Other races near Boston
Different organizers, within 40 miles, in the next three months
Run for the Dogs 5k - Boston
Codfish Bowl
Nuno 10K Run
Esplanade 5K Run & Walk
🏃 Plan Your Next Race in Boston
Find upcoming events by distance:
- Boston 5K Races 29 races
- 10K Run Events in Boston 4 races
- Boston Running Calendar 2026 42 races
Where this page comes from. Race details were last updated on . We re-check listings regularly and again in the week before race day.
- Entries, prices, waves and inclusions — the event's official registration page
- Temperature and humidity — Copernicus ERA5 reanalysis via Open-Meteo (CC BY 4.0)
- Elevation and terrain relief — Copernicus DEM GLO-90, ESA (CC BY 4.0)
- Comparisons and counts — Race Discovery calendar, 49 Boston events
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