4 Points has you covered if you forget your trail maps, or just want to check out the trail systems in Boise, McCall, Sun Valley or Stanley (and Bend and Portland, Oregon, too).
The maps are available $1.99 each, and they are available for IOS and Android phones.
The maps work in conjunction with your phone's GPS, so you can find your route along the trails. You can also get a 3-D view of the trails and get elevations profiles, and the app provides information about each trail, including length and elevation change.
The apps work without cell coverage or wi-fi, and a simple blue dot lets you know where you are at all times for easy navigation.
They're handy and inexpensive, so the maps are well worth the price. Check them out at here.