Free Topographical Maps for your Garmin Handheld GPS
Idaho Parks and Recreation Map
It references ALL Idaho public trails. You can create a track and print a map but not download GPX.
Colorado Trail Explorer
U.S. GEOLOGICAL SURVEY
USGS Topographical Maps: These classic "Topo" maps are free and printable but not editable. They are in a GeoPDF format. Read the "How to ?" instructions at the top of the web page.The terrago plugin for Adobe Reader allows the user to learn about the amazing properties of GeoPDF maps.
The Avenza Mapping App lets you use GeoPDF for GPS purposes but is not free. Better to avoid this product and use CalTopo.
USFS Palisades-Teton, Dubois, and Westside Ranger Districts.
US Forest Service "USFS" Maps
These are the best if you are in a national forrest
The Avenza Mapping App will open geo-enabled PDF
Forest Service Interactive Map
Yellowstone National Park
Click on a wilderness and then click on read more to find out regulations.
A "GIS" geographic information system shows information
on maps. Here is a good example from Wilderness Connect
Frank Church River of No Return Wilderness
Major State and National Trails
Continental Divide Trail
Nez Perce National Historic Trail
Great Western Trail
Other Public Places
City of Rocks and Castle Rocks, Idaho
Campgrounds, monuments, byways, recreation areas, rental cabins, wild and scenic rivers, state parks, wildlife management areas, wildlife refuges, National trails
Geologic Map of Idaho