Which geyser in Yellowstone is the world's tallest active geyser?

The world’s tallest active geyser is Steamboat Geyser in Yellowstone National Park. It is located in the Norris Geyser Basin, one of the hottest and most dynamic geothermal areas in the park.

During a major eruption, Steamboat can send water more than 300 feet into the air, making its columns higher than those of Old Faithful. Its eruptions are far less predictable, however: intervals can range from only a few days to many years. A major eruption can last from several minutes to more than two hours and is followed by bursts of steam and hot water.

Steamboat has two vents about 20 feet apart, with the northern vent producing the tallest water columns. The extinct or inactive Waimangu Geyser in New Zealand once produced even higher eruptions, reportedly reaching about 1,600 feet before a 1904 landslide altered its water system. That history explains why Steamboat is described as the tallest active geyser today.