Geyser
Yellowstone is the largest geyser locale, containing thousands of hot springs, and approximately 300 to 500 geysers. It is home to half of the world's total number of geysers in its nine geyser basins. It is located mostly in Wyoming, USA, with small portions in Montana and Idaho. Yellowstone includes the world's tallest active geyser (Steamboat Geyser in Norris Geyser Basin), as well as the renowned Old Faithful Geyser, Beehive Geyser, Giantess Geyser, Lion Geyser, Plume Geyser, Aurum Geyser, Castle Geyser, Sawmill Geyser, Grand Geyser, Oblong Geyser, Giant Geyser, Daisy Geyser, Grotto Geyser, the Fan & Mortar Geysers, & the Riverside Geyser, all in the Upper Geyser Basin which alone contains nearly 180 geysers.
Excelsior Geyser
The Excelsior Geyser pool discharges 4,000 to 4,500 gallons (15,100–17,000 l) 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 about 100 feet high, although some exceeded in both height and width. It is believed that the powerful eruptions damaged its internal plumbing system, and it now boils as a productive hot spring most of the time.
In 1985, Excelsior returned to activity for a 46-hour period from September 14 to 16. These eruptions were relatively small at but a few were as much as tall and 100 feet wide. All of these eruptions lasted about 2 minutes at intervals of 5 to 66 minutes.