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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!

Race Category

ws20KM

Running Stones

1

Distance

21 KM

Elevation Gain

500 M+

Start Date

Saturday 19th September 2026

Race Start

Natural Chimneys Park - 08:00

Max Allowed Race Time

06 Hours

Course Description

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

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: 06/30/2025

Revision History

  • Added elevation data
GPX File
Aid Station Chart

Aid Station Chart

Learn more about each aid station, including elevation gain/loss, cut-off times, and whether drop bags and crew access are available along the course.

Last updated: 6/3/2026