The Continental Divide National Scenic Trail

Congress established the Continental Divide
National Scenic Trail (CDT) in 1978, envisioning
a 3,100-mile primitive, challenging backcountry trail
from Canada to Mexico along the backbone of America.
Approximately 70 percent of the Trail is presently usable.
A short section traverses east-central Idaho,
near the border with Montana.
CDTrail.org