Vent Geyser

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.

Belgian Pool is a hot spring in the Upper Geyser Basin of Yellowstone National Park, Wyoming. Originally named Oyster Spring, it was renamed after a visitor from Belgium fell into it in 1929 with fatal results. The spring is less hot than other features in the area, at about 180 °F (82 °C), but still sufficiently hot for severe thermal burns. References to a "Belgian Geyser" in the 1930s may refer to this feature.

Penta Geyser sits a few feet off the path adjacent to Spasmodic Geyser in the Upper Geyser Basin of Yellowstone National Park, Wyoming, United States. Penta is located in the Sawmill Complex with geysers such as Sawmill Geyser, and Spasmodic Geyser. Penta Geyser has five vents, providing the basis of its name. Due to its location in the Sawmill Complex, Penta has a very close relation to the activity of Sawmill and the other geysers in the area. Penta's eruptions usually begin when the water levels in the complex are rising. This usually occurs after Spasmodic, and sometimes Tardy Geyser's eruptions begin. Before an eruption, water pools up near Penta. It can flow down toward Sawmill. Even very late in these stages, Sawmill can begin to erupt and cut off Penta, causing it to drain without an eruption. Penta Geyser usually erupts with Spasmodic, and ends a few minutes after Spasmodic stops. The eruptions are more common when the Sawmill Complex is in "Penta-Churn" mode.Penta was known at one time as "the Handsaw."

Economic Geyser is a geyser in the Upper Geyser Basin of Yellowstone National Park in the United States. Economic Geyser is a small, usually inactive geyser located between the Giant Geyser group and the Grand Geyser group. Economic Geyser was once a popular, frequently-erupting geyser until it became essentially dormant in the 1920s. Economic Geyser is believed to be named for its behavior during its active days. It is reported that most of the water ejected drained back into the vent after the eruption, thus making the geyser appear to conserve its water. It was most likely named by Frank Jay Haynes, the park photographer from 1883-1916. The temperature of the water in geyser pools and other geothermal features can be judged by the color of the bacteria living in the water. Changes in the size and color of bacteria mats at Economic Geyser imply that the geyser is heating up. Photographs of the geyser vent taken in the 1990s show a quiet pool very dark with algae. Photographs of the vent taken in 2006 show a pool of clear water with traces of the bacterial colors associated with higher temperatures.

Sawmill Geyser, named for the whirring sound it makes during its eruption, is a geyser in Yellowstone National Park, Wyoming, United States. The geyser was named by Antoine Schoenborn of the Hayden Geological Survey of 1871. Sawmill is the largest geyser in the Sawmill Complex, a region of geothermal features located in Upper Geyser Basin approximately 10 feet off the path. The geyser has an irregular pattern of eruption due to the underground structural interconnectivity which is characteristic of geyser complexes. Despite this, it tends to have a delay around 1 to 3 hours between eruptions. Often, Sawmill will erupt after the nearby Spasmodic Geyser, but only if Penta Geyser, another significant geyser in the complex, does not erupt first. If Penta erupts before Sawmill, Sawmill is cut off from water, and cannot erupt until the basin is reloaded, indicated by an eruption by Spasmodic. Another eruption indicator is when Sawmill fills with the rest of the geyser's water in the Sawmill Complex or starts to overflow, bubbles tend to rise to the surface. This indicates that an eruption is near. Sawmill drains after its eruptions, and if it had a large eruption prior, unusual behavior can occur in other geysers in the area. Sawmill was a frequent eruptor in recent years prior to January or February 2017, when it suddenly ceased eruptive activity for over four years. According to reports submitted to GeyserTimes.org, Sawmill's last observed eruption for over four years occurred during the morning hours of January 29, 2017. Sawmill Geyser resumed eruptive activity with an eruption at 2:00 AM on June 24, 2021.

Beauty Pool is a hot spring in the Upper Geyser Basin of Yellowstone National Park in the United States. It is connected to the nearby Chromatic Spring. When the water level in one of the two pools rises and overflows, the water level in the other decreases. These fluctuations in water level take place over periods ranging from a few weeks to several years. During this energy shift, the temperatures can change about 10 °F. Its temperature ranges from 164 to 175 °F (73 to 79 °C)

Spasmodic Geyser is a geyser located in the Upper Geyser Basin in Yellowstone National Park in the United States. Spasmodic Geyser's eruptions from the two craters can be up to 15 feet (4.6 m) high. Water can also erupt from a few inches to ten feet high from the approximately 20 vents. The intervals between eruptions are irregular, but most are in the 1-3 hour range. Spasmodic Geyser was named by A.C. Peale, from the 1878 Hayden survey team, for its erratic eruptions. Its temperature is about 92 °C (198 °F). Spasmodic Geyser is also connected to the nearby Penta Geyser, which is smaller. While Penta Geyser is erupting, there is no activity from Spasmodic Geyser. Activity from Spasmodic Geyser usually precede eruptions from Sawmill Geyser and Penta Geyser.

Chromatic Spring is a hot spring in the Upper Geyser Basin of Yellowstone National Park in the United States. It is connected to the nearby Beauty Pool. When the water level in one of the two pools rises and overflows, the water level in the other decreases. These fluctuations in water level take place over periods ranging from a few weeks to several years. During this energy shift, the temperatures can change about 10 °F (5.6 °C). Its temperature ranges from 164 to 175 °F (73 to 79 °C).

Crested Pool is a hot spring in the Upper Geyser Basin in Yellowstone National Park. The spring is 42 feet (12.8 m) deep. It is named for the "crest" which surrounds the pool. Although it is considered a spring, Crested Pool sometimes erupts like a geyser.

Turban Geyser is a geyser in the Upper Geyser Basin of Yellowstone National Park in the United States. Turban Geyser belongs to the Grand Group (or Grand Geyser Complex), and its eruption is tied to Grand Geyser. In the hours prior to Grand's eruption, Turban will have five-minute eruptions every 15–25 minutes. These eruptions measure 5–10 feet (2–3 m) in height. During Grand's eruption, Turban erupts continuously reaching up to 20 feet (6 m). Following an eruption of Grand, Turban will continue to erupt intermittently for an hour or so along with Vent Geyser. At times, it is not possible to see Turban erupting through the steam and spray of Grand Geyser. Turban Geyser was named for the similarity in appearance of the sinter deposits in its basin to the turban headpiece. Dr. A.C. Peale named the geyser in 1872.

Castle Geyser is a cone geyser in the Upper Geyser Basin of Yellowstone National Park. It is noted for the particularly large geyserite sinter deposits, which form its cone. These deposits have been likened in appearance to a castle.When the geyser was given this name in 1870, the top edges of the structure resembled the typical profile associated with the modern concept of a castle, having the appearance of a large keep, multiple turrets, and especially because of the crenellation along the top edges of what resembled its towers. As the drawing below shows the cone had distinctive appearance at the time. Over time the cone's shape changes because of the layers of mineral deposited in successive eruptions.

Bijou Geyser is a geyser in the Upper Geyser Basin of Yellowstone National Park in the United States.