Irish ultra-running sensation and former Olympian Caitriona Jennings has rewritten the record books, setting a phenomenal new women’s 100mile world record at the 2025 Tunnel Hill 100 Mile race.
In what was her debut attempt at the grueling 100-mile distance, Jennings crossed the finish line in an astonishing time of 12 hours, 37 minutes, and 4 seconds (12:37:04).
Jennings’s performance was a masterful display of pacing and endurance, successfully challenging and beating a record held by one of the sport’s legends:
New World Record: 12:37:04
Previous Record: The time eclipses the former world record of 12:42:40, which was set by American ultrarunner Camille Herron at the very same Tunnel Hill event in 2017.
Pacing Perfection: The Irish runner maintained an impressively consistent pace, averaging approximately 7 minutes and 34 seconds per mile across the entire 160.9 kilometer (100-mile) distance, finishing fourth overall in the race.
The Tunnel Hill 100 Mile is renowned for its flat, crushed-gravel course along the Tunnel Hill State Trail, a layout conducive to fast times, making it a prime location for record attempts.
Jennings, a native of Donegal, Ireland, already boasted an impressive résumé before this historic run:
She competed for Ireland in the marathon at the 2012 London Olympics.
She holds both the current Irish 50K record (set earlier in 2025) and the Irish 100K national record.
She is a former winner of the IAU 50K European Championships and has multiple top-10 finishes at the prestigious Comrades Marathon.
Speaking after the race, Jennings paid tribute to the previous record holder, stating she was “truly honoured to take this record from a true champion,” underscoring the respect within the ultrarunning community.
