The Mammoth-Gallatin region is a land of extremes. Elevations within the Mammoth area range from about 5,000 to 11,000 feet, with the lowest (in the park) near the Yellowstone River and the highest at Electric Peak, just miles away. The Gallatin Range, which sticks it thumb into Yellowstone for 20 miles from the north, includes about 19 peaks. Of these. Electric Peak (10,992 feet) dominates the northern end, and Mount Holmes (10,336 feet) marks the southern end.

The Gallatin Mountains are an uplifted range composed of stratified shales, limestones and sandstones dipping slightly northward. The composition of these limestones and the presence of oceanic fossils testifies that they once were part of large inland seas. Rugosa-or horn-corals, bryozoans and clam-shaped fossils are embedded on the slopes of these mountains.

The influence of limestone in the Mammoth area also has changed the makeup of the hydrothermal features. Elsewhere in the park, the surrounding rock is composed of silica dioxide, an essential element in the formation of geysers. But, here, the presence of calcium carbonate produces the unusual travertine terraces of Mammoth.

Osprey Falls Trail
Length: 1.0 miles, one way. Elevation change: Trailhead at 7,000 feet (500-foot drop). Trailhead: Located about three miles down the one way Bunsen Peak Road.

The trailhead for Osprey Falls is about three miles down the narrow, dirt Bunsen Peak Road. The turn off for this road is just above Rustic Falls and five miles south of Mammoth. The small parking area is on the right side of the road and is not well-defined, but should be marked. This area was burned extensively during the 1988 fires, and most of the Douglas firs-normally resistant to ground fires-burned. This indicates it was a hot, fast-moving fire. It will take several human lifetimes for this area to return to a mature Douglas fir forest.

The trail follows along the rim and descends by way of switchbacks to the bottom of Sheepeater Canyon. This canyon is an impressive 800-foot-deep gorge and ranks second only to the Grand Canyon of the Yellowstone. During the descent, the columnar basalt forming the Sheepeater Cliffs are visible across the canyon. These cliffs were named by P.W. Norris in honor of the Sheepeater Indians, a band of the Shoshone Indians, the only indigenous residents of the park who were known for their use of cliffs to herd and kill game animals.The trail ends at the base of Osprey Falls, which is hidden until then. Here, the Gardner River plunges 151 feet and the canyon walls rise more than 500 feet in view. But the spray created by this falls produces a cool, moist environment in contrast to the descent on a hot summer day. Nonetheless, spring or early summer is the best time to visit Osprey Falls-when the runoff is greatest.

Joffe Lake Trail
Length: 0.6 miles, one way.
Elevation change: Trailhead at 6,400 feet (80-foot gain). 
Trailhead: Located at the south end of the Mammoth trailer/ maintenance area. The turn off for this area is 1.3 miles south of the Mammoth Hotel, past the lower terraces at the first hairpin curve.

The trail for this shallow lake begins behind the Mammoth maintenance yard, on the south edge of the storage and construction area. (The maintenance shed, built in the late 1980s, is one of the largest buildings in Yellowstone.) This lake is especially popular, providing an easy ski tour during the winter. From the maintenance area, the lake is only 0.6 miles, and a small rise hides the lake until a hiker or skier is upon it.

This small one-and-a-half-acre lake was named in 1949 for Joseph Joffe (1896-1960). He was assistant superintendent for the National Park Service, but was known to catch fish illegally in the nearby Mammoth water-supply reservoir and claiming they were caught in the "CCC Lake" (renamed Joffe Lake). One of the lakes names came from the Civilian Conservation Corps (CCC), which had its camp established in the trailer yard. Other names for this lake include "Demonstration Pond," because fire equipment was demonstrated here, and "Hoodo Lake," for the limestone formation above the lake to the west. The mountain to the south is Bunsen Peak (8,564 feet), named in honor of Robert Wilhelm Eberhard von Bunsen (1811-1899). Bunsen originally pioneered the theory of geyser function and has his name attached to the Bunsen Burner.

Clematis Gulch Trail
Length: 3.3 miles, loop. Elevation change: Trailhead at 6239 feet (1221-foot, gain). Trailhead: Clematis Gulch Trail is located near Liberty Cap and heads west up the gulch.

Clematis Gulch Trail is a short hike that leads to trail access from Mammoth to Mammoth Beaver Ponds, Sepulcher Mountain, Snow Pass, and the Upper Mammoth Terraces.

The first section of this trail is the steepest and ascends about 350 feet in elevation through Douglas fir in a shaded, cool, moist gulch. After about a quarter mile the trail junctions with a trail accessing the Upper Mammoth Terraces to the south. The Clematis Gulch loop trail returns to this point. After about half a mile, the trail junctions with the Beaver Ponds Trail (see Mammoth Beaver Ponds Trail for description).

The trail continues to follow Clematis Creek for another half mile before junctioning again, this time with Sepulcher Mountain Loop Trail (see Sepulcher Mountain Trail for description). The north trail leads to Sepulcher Mountain and is the eastern half of the Sepulcher Mountain Loop Trail. Whereas the south trail begins a series of switchbacks and then junctions with the Snow Pass Trail. The downhill, or eastern, trail returns to Mammoth. The trail skirts the northern edge of the Upper Terraces and a side trip or a shortcut to the trailhead goes through the thermal basin.

Old Stagecoach Rd
(formerly the Old Mammoth-Gardiner Road) Length: 3.6 miles, one way. Elevation change: Trailhead at 6,239 feet (759-foot loss). Trailhead: Directly behind the Mammoth Hotel, is a dirt road cut into the hillside.

This old alternate stagecoach road brought visitors to Mammoth from the railroad stop at Cinnabar, before the twisting road that follows the Gardner River. It still is used today for vehicle traffic, but seldom so. This old road is an excellent path for birding, wildflowering, walking, mountain biking or winter ski-touring.

During summer, and especially in early spring, this is one of the best birding areas in the park. You'll find migratory songbirds, including Townsend's solitaire, waterpipit, finches, mountain bluebird, thrushes and sparrows, in the open terrain. While winter brings other wildlife, including bighorn sheep that have migrated from their higher summer pastures, mule deer, elk and antelope also are common along this road and trail. Most of this trail is open and exposed, and the wind during spring and fall can be fierce. Rocky Mountain junipers, Douglas firs and aspen are the primary trees found in the more protected slopes and gullies.

To the east of the road, across the Gardner River valley, is Mount Everts (7,841 feet). It was erroneously named for Truman Everts, who became separated from his group and wandered in the wilderness without his spectacles, horse or gear for 37 days before being found in an emaciated state near Tower Creek, but F.V. Hayden mistakenly named the creek just on the other side of this peak Rescue Creek as the location of Truman's rescue. To the west lies Sepulcher Mountain (9,652 feet) named by geologist Arnold Hague "on account of its low black appearance." After a short descent, the remaining distance is a gentle slope. The trail emerges at the North Entrance! low the town of Gardiner

Beaver Ponds Trail
Length from Mammoth to: Beaver Ponds 1.9 miles, one way. Beaver Pond Loop Trail 4.5 miles, loop. Elevation change: Trailhead at 6,239 feet (560-foot gain). Trailhead: Clematis Gulch Trail between Liberty Cap and the stone house at Mammoth.

The trail begins in Mammoth, between Liberty Cap and the stone house, and follows a small, shaded creek up Clematis Gulch. The first section of this hike is the steepest and ascends some 350 feet through Engelmann spruce and Douglas fir trees. The trail then splits, and the west trail heads toward Sepulcher Mountain. For the beaver ponds, continue north (right) and about two miles from the trailhead are a series of step-like beaver-created ponds along the stream. As beaver are mainly nocturnal animals, your best chances to see one are at dawn or dusk. After the beaver ponds and the return trip to Mammoth, the vegetation and views change. Quaking aspen trees are intermingled among sagebrush, and the vista of the Absaroka Range is to the north. The trail eventually parallels and joins the old Mammoth-Gardiner road, terminating behind the Mammoth hotel.

Lava Creek Trail
Length to: Undine Falls 0.5 miles, one way Confluence with Gardner River 2.5 miles, one way Mammoth School/footbridge 3.5 miles, one way Elevation change: Trailhead at 6,560 feet (760-foot drop). Trailhead: The trailhead is just less than 5 miles east of Mammoth, on the Mammoth-Tower Road at the Lava Creek bridge and picnic area.

The Lava Creek Trail is a one-way trail following Lava Creek and Gardner (note the different spelling from the town of Gardiner) River drainages. You can begin on the trail from either end; for a downhill hike, start at Lava Creek picnic area. The picnic area and parking is at the pull off near the Lava Creek bridge. But the trailhead is to the north, across the highway and on the east side of the bridge and creek.

From the bridge, the trail follows Lava Creek among Douglas firs and then begins a steep descent into Lava Creek Canyon. At the start of the canyon. Lava Creek plunges over a double waterfall. The upper terrace is 60 feet high and the lower one is 50 feet high. The Hague party named Undine (pronounced Un-deen) Falls in 1885 for mythical water nymphs who, in folklore, live around waterfalls and acquire mortal men's souls by marrying them and bearing their children.

The trail continues down the canyon along open, exposed slopes, following Lava Creek until it merges with the Gardner River. This section of the river is less tumultuous than it is upstream. Springs and seeps line the shore, and beaver have taken up residency here. Mount Everts is the steep. Rocky Mountain juniper sloped mountain rising from the river to the east. During winter and early spring bighorn sheep can often be spotted traversing the steep slope. The hike ends at the footbridge crossing the Gardner River, and the trail emerges behind the Mammoth Elementary School. There also is a service road leading to the bridge but it is easily accessed by foot from the Mammoth campground, which is across the highway from the school.

Rescue Creek Trail
Length from Blacktail Trailhead to: Blacktail Deer Creek Trail junction North Entrance Trailhead (suspension bridge) 7.0 miles, one way. Elevation change: Trailhead at 6,640 feet (1,280-foot loss, but 1,520-foot loss overall).

Trailhead: Rescue Creek Trail can be approached from two directions: the North Entrance trailhead or the Blacktail Deer Creek Trailhead. The Blacktail Trailhead, located 6.6 miles east of the Mammoth Hotel on the Mammoth-Tower Road, provides a downhill direction. The North Entrance trailhead is located about a half mile south of the entrance station.

Rescue Creek was erroneously named for the rescue site of Truman Everts, who became separated from his group and wandered in the wilderness without his spectacles, horse or gear and lived on the roots of elk thistle for 37 days before being rescued. His rescue location, however, was near Tower Creek, but F.V. Hayden mistakenly named this as the location and it has borne the name Rescue Creek ever since.

The Rescue Creek Trail is a popular spring or early summer hike because it generally is snow-free before other park trails. Also in spring, pink bitterroots, the Montana state flower, cover the small, windswept ridges just beyond the parking area. The trail begins in open sagebrush country and soon junctions from Blacktail Deer Creek Trail (see Blacktail Deer Creek Trail for description) where Rescue Creek Trail heads west up Rescue Creek. From here, the trail climbs gradually through aspens and open meadows. Several small ponds or kettle lakes, left by retreating glaciers, provide habitat for migrating waterfowl. In spring, ruddy ducks frequently use these ponds on their northern migration.

The trail then begins a steep descent of nearly 1500 feet to the Gardner River. Rattlesnake Butte, to the north, blocks the view of the Yellowstone River. At the river is the lowest elevation in the park, and occasionally western rattlesnakes and bull snakes are found along this region. The trail then skirts the northern base of Mount Everts before crossing the Gardner River via a well-built foot and horse bridge. The northern section of the Rescue Creek Trail, along the lower slope of Mount Everts, is one of the best hikes for viewing wildlife early in spring, or late in fall (October-November). Elk, mule deer, antelope and bighorn sheep winter in this region. As a result, wintering elk and deer shed their antlers on the open meadow. This trail, traditionally, has been used as a corridor for elk-antler poachers, locally called horn hunters.