Yellowstone is world-famous for its natural heritage and beauty - and for the fact that it holds half the world's geothermal features, with more than 10,000 examples. Travelers to Yellowstone can view more than 300 geysers (such as "Old Faithful"), pools of boiling mud, and an amazing assemblage of wildlife, such as grizzly bears, wolves, bison and elk, all while standing on the surface of the Earth's largest known "super-volcano".

Mammoth

 • Mammoth Hot Springs. Mineral-laden hot water flows from springs, depositing calcite and other substances in its wake. Over time, these deposits form large terraces and other shapes. Some of the terraces grow several inches per day.
 • Fort Yellowstone. The historic center of activity during the United States Army's tenure of the park.
 • Bunson Peak. The hike to the top of this 8,564 peak takes approximately three hours round trip. The peak overlooks the old Ft. Yellowstone area and it is only a gradual climb. Bring water and snacks (and bear bells if you think they'll work).

Norris

 • Norris Geyser Basin. One of the parks many spectacular thermal areas, and home to Steamboat Geyser, the world's largest geyser, which can throw water more than 300 feet into the air when it erupts.
 • Roaring Mountain. A collection of steam vents and hot springs which make noises ranging from a nearly inaudible whisper to a roar that can be heard miles away.
 • Gibbon River.
 • Virginia Cascades.

Madison

 • Artist Paint Pots. A half-mile hike takes you past many colorful hot springs, steam vents and bubbling mud pots.
 • Monument Geyser Basin.
 • Gibbon Falls.
 • Madison River.
 • Terrace Springs.
 • Firehole Canyon Drive and Firehole Falls.
 • National Park Mountain.

Geyser basins, including Old Faithful

 • Upper Geyser Basin. The most popular visitor area in the park, the Upper Geyser Basin is home to the largest number of geysers in the park, with over 100 located within a one square mile area. Boardwalks allow access to the most interesting areas. Do not leave the trails; the surface here is thin and unstable and has a real chance of depositing you in a boiling pool of water if you walk where you're not supposed to.
 • Old Faithful The world's most famous geyser, with large eruptions occurring an average of about once every hour and a half. Despite its reputation for having eruptions you can set a watch to, the timing between each eruption has actually been increasing over the past several decades. Rangers are able to predict the geyser's eruptions to within about 10 minutes, provided the duration of the previous eruption is known.
 • Other geysers in Upper Geyser Basin that are well enough understood to be predictable (sort of!) are Grand Geyser (probably the finest predictable geyser in the park), Castle Geyser, Daisy Geyser, and Riverside Geyser. Check at the Old Faithful visitor center for predictions, which will have uncertainties of an hour or so associated with them, sometimes more.

 • Lower Geyser Basin. Unlike Upper Basin, most active areas here are accessible by car. Great Fountain Geyser is the largest geyser in this group, is easily reached by car, and is well enough understood to be predicted, after a fashion; check at the Old Faithful visitor center, and when you get to the geyser, check the bulletin board again, as its behavior allows periodic updating of the predictions.
 • Midway Geyser Basin. This geyser basin is on a hill overlooking the Firehole River. The runoff from its thermal features flows into the river, leaving steaming, colorful trails in its wake. • Grand Prismatic Spring. Perhaps this geyser basin's most famous feature, this is a mass of sapphire blue hot water with bands of yellow and orange around its edges. This spring is more than 300 feet across.
 • Excelsior Geyser once had such violent eruptions that it seems to have blown itself up. This geyser hasn't erupted in years, but it still discharges over 4000 gallons of water per minute into the nearby Firehole River.
 • Lone Star Geyser Basin. This and the following are more "Do" than "See," as they require some hiking to reach them. The route takes off from the loop road south of Upper Geyser Basin and follows an old, now-closed road for a total of about 3 miles (5 km). Bicycles can make it most of the way to Lone Star.
 • Shoshone Geyser Basin. Serious hiking is required to reach this remote basin, which is beyond Lone Star and a good 7 miles (12 km) one way from the trailhead.

Grant Village

 • West Thumb Geyser Basin. With a little imagination, Yellowstone Lake looks like a left hand reaching southward. This thermal area is along the western thumblike section of the lake. Several geysers and hot springs (even a couple that are just a few inches across!) are in this area, including the following two sights:
 • Abyss Pool. There is an optical illusion with this brilliant blue hot spring that makes it look bottomless.
 • Fishing Cone. In the past, people used to catch fish in Yellowstone Lake and then cook the fish by dipping them into this partially submerged hot spring. This stunt is no longer allowed.
 • Shoshone Lake.

Lake Area

 • Yellowstone Lake.
 • Mud Volcano/Sulphur Cauldron. This area of the park has pools of mud that are constantly seething and boiling.  • Mud Volcano This was once a hilltop thermal feature that would hurl mud into the nearby trees during eruptions. One particularly large eruption blew apart the Mud Volcano, leaving a hot, bubbling mud pool at the base of the hill.
 • Dragon's Mouth Spring Steam and hot water surge forth from within an underground cavern, creating waves in the surface mud pool. These surges of water and steam reverberate inside the cavern and make loud thumping or roaring sounds.
 • Sulphur Cauldron This vast hot spring is strongly acidic thanks to the action of microorganisms.
 • Natural Bridge.

Canyon

 • The Grand Canyon of the Yellowstone. Chemical processes over time have left stripes and patches of different colors in the rock of this canyon. Trails lead along the north and south rims of the canyon, but while traveling the entire trail in one day is possible, it makes for a long and tiring day. Best to make it two shorter (~3 hour) day hikes. If you're a photo buff, plan your walks so the sun illuminates the opposite side for great pictures.
 • The Upper and Lower Falls of the Yellowstone.
 • Hayden Valley.
 • Mt. Washburn. One of the best places in the park for spotting bighorn sheep, a trail leads up the mountain to a lookout tower near the 10,243 foot summit. The altitude may affect some hikers, so it is best to be acclimatized to the higher elevation before attempting this hike. In addition, bring extra layers, even in the summer, since the top can be windy and cold.

Tower-Roosevelt
 • Specimen Ridge.
 • Petrified Tree.
 • Tower Fall.
 • Calcite Springs.