Grindstone 21K is the 21.0km trail race at Grindstone Trail Running Festival by UTMB 2027 (Natural Chimneys Park, United States). The race starts on September 25, 2027 at 08:00 AM. It starts in Natural Chimneys Park. The time limit is 6 h.
Run the climb at race pace, build your speed on the downhill, and go all out at the finish.
The course climbs 500m+. With 24m/km of climbing, the course is predominantly runnable. By gradient, 20% of the distance is uphill, 19% downhill and 61% flat. The longest climb runs 4.6km at an average 7.0% grade (321m of vertical). The longest descent runs 2.5km at an average 9.2% grade (227m of vertical). The steepest climb averages 28.7% over 0.4km. The steepest descent drops at 21.6% over 0.4km. Surface: 35% trail, 31% road, and 22% smooth.
The course is runnable enough that trekking poles are not needed.
There is too little runnable descent to damage the quads: plan the race around climbing and fuelling.
This page has a pacing and nutrition planner, a gradient matrix, an interactive elevation profile and historical weather for Grindstone 21K.
Other distances of Grindstone Trail Running Festival by UTMB 2027Grindstone 100M (167km)·Grindstone 100K (100km)·Grindstone 50K (50.0km)
Other editions of Grindstone 21K2025
Official websitegrindstone.utmb.world