Alyssa Clark

About

Alyssa Clark is an American ultrarunner and endurance adventurer from Bennington, Vermont who graduated from Williams College in 2015 and quickly established herself as one of the sport's most versatile and determined competitors. A plant-based On Running athlete, she lives in California with her husband Codi, a Navy diver stationed at Naval Base Coronado. Her race record spans formats from mountain ultras to multi-day events: wins at the Moab 240, the Canyons 100, and the HURT 100 on Oahu — where she became the first woman to break 24 hours — alongside an FKT for the 137-mile perimeter of Oahu. In 2023 she ran 95 consecutive marathon-distance efforts in 95 days, setting an American record and a pending women's Guinness World Record before illness ended the attempt. She was runner-up at the Canyons 100M by UTMB in 2026.

Notable Wins

• — Moab 240
• — HURT 100 (first woman sub-24h)
• — Canyons Endurance Runs by UTMB 100M
• — Oahu Perimeter FKT (137 miles)
• — 95 consecutive marathon days 2023 (American record)

Race History