From the Missouri State Parks website (https://mostateparks.com/page/59256/geocaching-and-letterboxing)
Geocaching is a popular game using global positioning systems (GPS) to locate hidden containers, called caches. Letterboxing is similar, except clues, map coordinates or compass bearings are used to find hidden treasures. Both activities are permitted in Missouri state parks and are a great way to get kids and adults outdoors. There are many caches already placed in Missouri state parks.
If you would like to place a cache in a Missouri state parks, please follow these steps and guidelines.
- Complete an Official Geocaching/Letterboxing Placement Permit. Facility managers will review each permit and decide if the cache follows guidelines.
- Caches are not to be placed in sensitive archaeological, historical or ecological areas such as historical buildings, caves or locations that contain rare plant species. Before placing cache, please check with the facility manager for allowed areas. No digging or disruption of the ground is permitted when placing a cache. Once the cache is placed, you must inform the facility manager of the exact location.
- An explanation of the geocaching/letterboxing activity must be included in the container.
- The cache must contain family-friendly content.
- A cache owner is limited to two permits in one faciltiy at one time.
- Permits are valid for 12 months from the approved date.