Montana State Parks
The Montana Bureau of Land Management
https://www.blm.gov/montana-dakotas
The U.S. National Wildlife Refuge System
Montana Fish, Wildlife & Parks
Yellowstone National Park
http://www.nps.gov/yell/planyourvisit/hiking.htm
Glacier National Park
http://www.nps.gov/glac/planyourvisit/hikingthetrails.htm
National Forest Service
http://www.fs.fed.us/maps/forest-maps.shtml
Montana Wilderness Association