Yellowstone National Park: Narrow Gauge

Link some of Yellowstone National Park's most striking thermal features on this 5.2-mile loop near Mammoth Hot Springs.

Travel beyond Mammoth Hot Springs to discover some of Yellowstone's more extraordinary thermal features, as well as classic views of Mount Everts, Bunsen Peak and the Gardner Canyon. Starting from the Mammoth Terrace Trail, turn right onto the Sepulcher Mountain Trail to head toward Hymen Terrace, a broad travertine formation backdropped by the stately Mount Everts.

Continuing to the west, pass through a grassy meadow frequented by grizzlies as the trail climbs upward at a moderate grade. After winding through woods dotted with Douglas firs and aspens, the trail flattens out around mile 2.1 and crosses into a broad, grassy field, offering superb panoramas of Mammoth Hot Springs, the surrounding mountains, and a pine-blanketed countryside.

From the grassy plateau, it's an easy downhill to the Orange Spring Mound at mile 3.9. This 20-foot-high feature, which owes its signature orange hue to microbial bacteria, has grown so large that it actually hides the spring that feeds it. Less than a half mile further, the trail visits the Narrow Gauge Terrace where a set of terraced, travertine pools emit steam and vapors. Break out your camera to document this striking geothermal feature before heading back to Waypoint 4 and turning right to complete the loop.

MORE PARK INFO Yellowstone National Park, (307) 344-7381;

-Mapped by Jeff Chow

Trail Facts

  • Distance: 8.4



Location: 44.9730413, -110.7039768

Head north on the Mammoth Terraces Trail.


Location: 44.9737395, -110.7042825

Turn left to head west toward Hymen Terrace on the Sepulcher Mountain Trail.


Location: 44.973444, -110.705065

Pass Hymen Terrace, a low, steaming feature framed by Mount Everts in the background. Keep your eyes open for elk.


Location: 44.9732538, -110.7083434

Bear right at Y-junction on the Sepulcher Mountain Trail; bypass the Howard Eaton Trail. Cross the bridge to continue your steady but moderate climb upward.


Location: 44.9753562, -110.7138956

Turn left to stay on the Sepulcher Mountain Trail at the Y-junction. Caution: Grizzlies frequent this grassy area.


Location: 44.974785, -110.723527

Cross a hillside bridge. The grade lessens here as the trail weaves through aspen groves and Douglas firs.


Location: 44.973164, -110.727597

Veer left off the Sepulcher Mountain Trail onto the Clagett Butte Trail. Walk over a footbridge that crosses a small stream and begin a very brief descent.


Location: 44.9712804, -110.7271135

Cut between a horseshoe-shaped pond on the left and a small green pond on the right as the trail begins swinging uphill again.


Location: 44.966394, -110.726848

Pop out of the forest and into a flat sagebrush meadow that showcases spectacular views of Bunsen Peak (named for the guy who invented the Bunsen Burner), Gardner Canyon, Mammoth Hot Springs, Mount Everts.


Location: 44.9639553, -110.7267809

Stay on the Claget Butte Trail at the Y-junction.


Location: 44.96085, -110.728021

Turn left at the Y-junction to bypass the trail on the right leading to Snow Pass.


Location: 44.9608618, -110.7189113

Flanked by juniper bushes, fir and moss, the trail passes by formations of travertine (a chemical precipitate of calcium bicarbonate that comprises the terraces). These sedimentary rocks suggest the presence of a hot spring in the area at one point.


Location: 44.960388, -110.717038

To the right, pass a narrow, gaping cleft that plunges down 50 feet.


Location: 44.959241, -110.7151079

At the Snow Pass Trail junction, hang an immediate left onto the unmarked trail.


Location: 44.9666729, -110.7151401

Hit the Orange Spring mound, a 20-foot high, 30-foot long, calcium carbonate deposit. The mound's several spring outlets cause the feature to transform at a rapid rate. Look for the dead stalks of suffocated trees, cemented into the mound's rounded-out structure.


Location: 44.969563, -110.7105669

Turn right at the Y-junction to hit Narrow Gauge Terrace, a highly active feature that has grown over six feet in the past three years. Surrounded by terraced hot pools and trees struggling to survive, the terrace emits smells of rotten eggs (actually sulfur).


Location: 44.9695042, -110.7100815

After getting your fill of Narrow Gauge, head north to follow the trail back to Waypoint 4 and turn right to reach the trailhead.

Narrow Gauge Terrace

Location: 44.969514, -110.710378

Grizzly Bear

Location: 44.975238, -110.716105

Back-Scratching Grizzly

Location: 44.975307, -110.717332

Small Pond

Location: 44.9717965, -110.7274461

Bunsen Peak

Location: 44.96473, -110.726842

Jaw Bone

Location: 44.962539, -110.726641


Location: 44.961488, -110.727051


Location: 44.961392, -110.727244

Narrow Gorge

Location: 44.9603797, -110.7168031


Location: 44.961698, -110.715668

Orange Spring Mound

Location: 44.9644943, -110.7162237

Steam From Orange Spring Mound

Location: 44.9667849, -110.7150757

Front View of Orange Spring Mound

Location: 44.966726, -110.7151133

Orange Spring Mound Profile

Location: 44.967191, -110.7144454

Orange Spring Mound Close-Up

Location: 44.9672175, -110.7143998

Orange Spring Mound Texture

Location: 44.9672479, -110.7143542

Round Pools at Narrow Gauge Terrace

Location: 44.968249, -110.711821

Dead Trees at Narrow Gauge Terrace

Location: 44.969432, -110.710684

Steaming Pools at Narrow Gauge Terrace

Location: 44.969441, -110.710549

More Views: Narrow Gauge Terrace

Location: 44.969441, -110.710549

Submerged Trees: Narrow Gauge Terrace

Location: 44.969441, -110.710549

Steaming Falls at Narrow Gauge Terrace

Location: 44.969356, -110.710501

Sunset at Narrow Gauge Terrace

Location: 44.969514, -110.710378

Lone Tree at Narrow Gauge Terrace

Location: 44.96957, -110.710143

Narrow Gauge Terrace Sign

Location: 44.969342, -110.710525


Location: 44.970155, -110.709885