This is a letterbox, please don't take the stamp
At the posted coordinates you will find a trail marker.
If the dot on the marker has 2 colors the final is at N39 02.817 W84 07.817
If 1 color then N39 02.795 W84 08.181
You are looking for a preform in a small maple tree.
ODNR Permit EF-05-17-24
See https://coord.info/GCARY9Y for parking and trailhead info
Here's a great park map https://drive.google.com/file/d/1vN-M0wnOxctzyuZbwmqZ-M6wVak81Z9Z/view?usp=sharing