21K
The Grindstone half marathon course throws a killer climb, a fun ridge run, and a bombing downhill at you, all while still offering a blazing fast start and finish for those interested in a little taste of everything!
Course Description
Starting and finishing at the historic Natural Chimneys, the Grindstone half-marathon course provides you a fast start in rolling country before entering the forest at the Bear Trap access. From there the course follows Lick Run taking you up the short but steep climb to the Narrow Back Mtn ridgeline. Follow the ridgeline before flying back down Tillman Trail east, along the Narrow Back forest access, retracing a fast finish to the base of the towering limestone chimneys and finish line festival.
*Courses are subject to change.
GPX File
**PLEASE NOTE: This is the 2026 GPX File and is subject to change for 2027.
Download the 100 Mile course GPX file below. Remember to ALWAYS follow course markings on the day of the race, as there might be slight alterations from the Course Maps and GPX File.
Your recorded distance may vary from our reported distance by as much as +/- one mile due to your device recording interval, the terrain, and dense tree canopy cover.
Last updated: 09/03/2026
