Darkness pools in central Idaho, where large swaths of designated wilderness hold the line against development and light pollution. In 2018, a 1,416-square-mile tract in Sawtooth National Forest became the first place in the United States to be designated an International Dark Sky Reserve by the International Dark-Sky Association, highlighting a peerless chance to meld untouched land with unmarred skies. You can’t fully experience the place on an overnight. Instead, brush up on off-trail navigation and go for full immersion on the 70-mile Grand Sawtooth Loop. Start at Grandjean Campground and hike clockwise, sleeping under star-dusted skies at Camp Lakes, Baron Creek, Lower Cramer Lake, Ardeth Lake, and Elk Lake.
Trailhead Grandjean Campground Season Summer Permit Required (free); self-register at the kiosk at Grandjean Campground.