Excelsior Geyser Crater, formerly known as Excelsior Geyser, is a hot spring in the Midway Geyser Basin of Yellowstone National Park in the United States. Excelsior was named by the Hayden Geological Survey of 1871. Possibly the only known photograph of Excelsior in full eruption was taken by Frank Jay Haynes in 1888.
The Excelsior Geyser pool discharges 4,000 to 4,500 gallons (15,100–17,000 l) of 199 °F (93 °C). of water per minute directly into the Firehole River. In the late 19th century (there was possibly some activity in 1901 too) it was an active geyser that erupted frequently. Most eruptions were "only" 100 feet high, but some exceeded 300 feet (91 m) and were as wide as they were high. It is believed that powerful eruptions damaged its internal plumbing system, and it now boils as a productive hot spring most of the time.