Frosty Fat Sass
West Orange, United States • 31 Jan 2026
The Frosty Fat Sass is an annual trail running and hiking event held at South Mountain Reservation in West Orange, New Jersey. Scheduled for January 31, 2026, this 9th edition offers participants options to run or hike a 5K loop, or join timed 3-hour and 6-hour challenges, including a new rucking division with weighted packs. The course features a mix of wide dirt trails and technical singletrack with rocks and roots, totaling 289 feet of elevation gain.
This self-supported "fat-ass" event emphasizes community spirit, with no aid stations or finishers' swag. Proceeds benefit the South Mountain Conservancy, supporting local trail preservation and education. Family-friendly activities and discounts for youth, military, and seniors enhance the welcoming atmosphere. Visit the organization's website for the most recent information.