The geothermal areas of Yellowstone include several geyser basins in Yellowstone National Park as well as other geothermal features such as hot springs, mud pots, and fumaroles. The number of thermal features in Yellowstone is estimated at 10,000. A study that was completed in 2011 found that a total of 1,283 geysers have erupted in Yellowstone, 465 of which are active during an average year. These are distributed among nine geyser basins, with a few geysers found in smaller thermal areas throughout the Park. The number of geysers in each geyser basin are as follows: Upper Geyser Basin (410), Midway Geyser Basin (59), Lower Geyser Basin (283), Norris Geyser Basin (193), West Thumb Geyser Basin (84), Gibbon Geyser Basin (24), Lone Star Geyser Basin (21), Shoshone Geyser Basin (107), Heart Lake Geyser Basin (69), other areas (33). Although famous large geysers like Old Faithful are part of the total, most of Yellowstone's geysers are small, erupting to only a foot or two. The hydrothermal system that supplies the geysers with hot water sits within an ancient active caldera. Many of the thermal features in Yellowstone build up sinter, geyserite, or travertine deposits around and within them.
Mammoth Hot Springs is a large complex of hot springs on a hill of travertine in Yellowstone National Park adjacent to Fort Yellowstone and the Mammoth Hot Springs Historic District. It was created over thousands of years as hot water from the spring cooled and deposited calcium carbonate. Because of the huge amount of geothermal vents, travertine flourishes. Although these springs lie outside the caldera boundary, their energy has been attributed to the same magmatic system that fuels other Yellowstone geothermal areas.
Daisy Geyser is a geyser in the Upper Geyser Basin of Yellowstone National Park in the United States.
Splendid Geyser is a geyser in the Upper Geyser Basin of Yellowstone National Park in the United States.
Comet Geyser is a geyser in the Upper Geyser Basin of Yellowstone National Park in the United States.
A-0 Geyser is a geyser in the Lower Geyser Basin of Yellowstone National Park in the United States.
Spindle Geyser is a geyser in the Lower Geyser Basin of Yellowstone National Park in the U.S. state of Wyoming.
Botryoidal Spring is a fountain-type geyser in the Lower Geyser Basin of Yellowstone National Park in the United States.
Atomizer Geyser is a cone geyser in the Upper Geyser Basin of Yellowstone National Park in the United States. Atomizer Geyser is part of the Cascade Group which also includes Artemisia Geyser. The geyser is named for a fine mist resembling the spray from an atomizer that is ejected during major eruptions.
Young Hopeful Geyser and Grey Bulger Geyser are two separate geysers that share the same pool in the Lower Geyser Basin of Yellowstone National Park in the United States. Both geysers are part of the Black Warrior Group which includes Artesia Geyser and Steady Geyser.
Excelsior Geyser Crater, formerly known as Excelsior Geyser, is a dormant fountain-type geyser in the Midway Geyser Basin of Yellowstone National Park in the United States. Excelsior was named by the Hayden Geological Survey of 1871.
The Great Fountain Geyser is a fountain-type geyser located in the Firehole Lake area of Lower Geyser Basin of Yellowstone National Park, Wyoming. It is the only Lower Geyser Basin feature that the park makes predictions for.
Black Pool is a hot spring in the West Thumb Geyser Basin of Yellowstone National Park in the United States.
Crested Pool is a hot spring in the Upper Geyser Basin in Yellowstone National Park. The spring is 42 feet deep. It is named for the "crest" which surrounds the pool. Although it is considered a spring, Crested Pool sometimes erupts like a geyser.
Doublet Pool is a hot spring in the Upper Geyser Basin of Yellowstone National Park, Wyoming.
White Dome Geyser is a geyser located in the Lower Geyser Basin in Yellowstone National Park in the United States.
Opal Pool is a hot spring in the Midway Geyser Basin of Yellowstone National Park, Wyoming. Opal Pool usually has a temperature of approximately 132 °F (56 °C). Though usually active as a hot spring, Opal Pool is considered a fountain-type geyser.
Turquoise Pool is a hot spring in the Midway Geyser Basin of Yellowstone National Park, Wyoming. Turquoise Pool has a temperature between 142 and 160 °F and was named by members of the Hayden Expedition of 1878.
Bulger Geyser is located in the Upper Geyser Basin of Yellowstone National Park, Wyoming. Bulger Geyser is 200 feet (61 m) south of Grand Geyser. It erupts frequently, with both major and minor eruptions. As with most geysers, the minor eruptions are the most common. They have a duration of seconds. Major eruptions are infrequent, but they have durations as long as 12 minutes. Either way, the play consists of somewhat vigorous bursting 1–12 feet high.
West Triplet Geyser is a geyser in the Upper Geyser Basin of Yellowstone National Park, Wyoming. West Triplet Geyser is 85 feet (26 m) south of Grand Geyser. Its activity is related to that of Grand and Rift geysers. West Triplet erupts to a height of about 10 feet (3.0 m), usually during Grand's quiet periods. Before 1947 it displayed regular activity, erupting about every three hours.
