Heart Lake Trail

Heart Lake Trail is an out-and-back through Yellowstone’s southern backcountry, from Heart Lake Trailhead (8N1) to the northwest shore of Heart Lake. The route climbs gently for much of the way, then drops through a geothermal basin to the water. It is a long, remote walk, not a quick viewpoint stop. The mapped line runs about 7.75 miles each way. The trailhead description gives about 7.2 miles to the lake, while trip accounts describe 7.5 to 8; this record uses 15.5 miles round trip to match the mapped approach. Allow about nine hours and turn around if your pace or daylight makes the full return a stretch.

The first 5.5 miles climb through a mix of burned forest, surviving groves and young trees returning after the 1988 fires. It is a gradual start, but the distance accumulates before the lake even comes into view. One hiker account found mosquitoes worst in this wooded stretch, so bring repellent when insects are active.

Around 5.5 miles in, the trail reaches a ridge with a couple of small hot springs and the first view of Heart Lake below. The water looks close from here; it is still roughly two miles away. This is the best early place to pause and take in the basin. For a photo, frame the lake with the geothermal ground in the foreground, but stay on firm, established tread.

Past the ridge, the route descends and switchbacks across Witch Creek, which is warmed by nearby geothermal activity. It then winds through trees, meadows and hot-spring ground toward the shore. The basin’s alkaline pools have drawn researchers studying microbial life. Their crust can be dangerously thin: stay on the trail and never cross thermal ground to shorten the route or get a closer look.

The route reaches the lake’s northwest shore beneath Mount Sheridan, a 10,313-foot peak in the Red Mountains. The shoreline is the turnaround for this day hike. The named corridor continues beyond the lake to the South Boundary Trail junction; its full through-route is 17.4 miles one way, a separate backcountry itinerary rather than the return trip mapped here.

Heart Lake Trail is closed every year from April 1 through June 30 because of bear activity. Park rules call for hiking in groups of three or more, staying together and remaining on established trails; carry bear spray. Pets are not allowed. An overnight camp requires a backcountry permit. Start at Heart Lake Trailhead (8N1) off the South Entrance Road; the trailhead has an information kiosk and vault toilet. Food service and potable water were not listed, so arrive with what you need for a full day.