Grindstone 100K is a 105 km ultra trail of Grindstone Trail Running Festival by UTMB 2025 in Swoope, United States. The race starts on September 18, 2025. The course climbs 3146 m+ and descends 3142 m−, between a low point of 405 m and a high point of 1325 m. By gradient, 33% of the distance is uphill, 31% downhill and 36% flat. The longest climb runs 4.7 km at an average 6.4% grade (300 m of vertical). The longest descent runs 5.0 km at 11.0% (549 m of vertical). Surface: 56% trail, 29% smooth, 11% road, and 5% extreme. Flat-equivalent effort: 125.6 FlatKM.
157 finishers completed the 2025 edition. Men's winner: Mead Binhammer (United States) in 9:38:11. Women's winner: Sandi Nypaver (United States) in 11:24:54.
This page has the full results and splits, interactive elevation profile, gradient matrix, pacing and nutrition planner and weather climatology for Grindstone 100K.
Other distances of Grindstone Trail Running Festival by UTMB 2025Grindstone 100M (169 km)·Grindstone 50K (52.0 km)·Grindstone 21K (21.0 km)
Other editions of Grindstone 100K2026
Official websitegrindstone.utmb.world
