The Timberman Triathlon was an annual triathalon event based at Ellacoya State Park from 2000-2016.

At the last event, on Saturday, August 20th, 2016, a short, 18.4 mile “sprint” triathalon, consisting of a 0.3 mile swim, a 15 mile bike ride, and a 3.1 mile run, was held, attracting about 1400 athletes. On Sunday, August 21st, 2016, the main event was held, a 70.3 mile, “half-ironman” triathalon,  featuring a 1.2 mile swim in Lake Winnipesaukee, a 56 mile bike ride, and a 13.1 mile run, Nearly 2000 athletes competed in this event, which was an official qualifier for the Ironman World Championships. 

Although the Timberman was created and developed locally, the event was sold to the World Triathalon Corporation. After a 5-year hiatus, the event resumed at Opechee Park in Laconia on August 22, 2021. The swimming portion of the Triathlon was held in Lake Opechee, and the running and biking portions also departed from there. The event was held a second time on September 18, 2022, then discontinued. During its two-year revival, the event was known officially as the “Ironman 70.3 Timberman“, but still referred to locally as the “Timberman Triathalon”.

There remain about 180 Ironman events held in over 20 countries.