Jefferson County in Colorado used to have a policy where you had to apply for a permit for 'boxes. They're one of the largest landholders along the Front Range (the part of the Rocky Mountains facing east and the largest area of population in the state)

Now, as long as 6 very basic guidelines are observed, it's letterboxing heaven. No permits, no muss, no fuss! You should also know that Jeffco (as it's known locally) have volunteers who regularly check on boxes and caches.

Here's the link with the specifics (geocaching and letterboxing):

http://jeffco.us/Open-Space/Documents/Activities-Documents/Geocache-Guidelines/

Received from Cheyenne Mt State park:
I am a Park Ranger at Cheyenne Mountain State Park, and we are having issues with unapproved letterboxes on the park. While we do allow letterboxing and geocaching, we require that the Park Manager approve all placement before publication to make sure we are protecting the vegetation, wildlife and other resources on the park. We have had letterboxes left in non-sustainable places with scented items inside that attract animals, and recently one was destroyed leaving trash and contents all over the area. I have contacted the placers but no response.

Are letterboxes approved by an admin before pusblication on the site? If so, can you require that any placed in Colorado State Parks is being placed with park permission, especially here at Cheyenne Mountain? If permission is not granted, letterboxes will be removed. We would like to work with the placers, but we need a better system of contacts and also we will require exact locations so we can visit the site before approval.

Please contact me via email or at 719/287-0813 to discuss.

Thank you,
Kristen Sherwood
Park Ranger
Cheyenne Mountain State Park