Grand Geyser, Hydrothermal fountain in Upper Geyser Basin, Yellowstone National Park, United States.

Grand Geyser is a hydrothermal fountain in the Upper Geyser Basin of Yellowstone National Park. It shoots multiple bursts of heated water during each eruption cycle, with columns reaching up to 200 feet (60 meters) high.

Members of the Hayden Expedition named Grand Geyser in 1871, having seen no larger geyser on their survey of the Yellowstone region. For much of the park's history its eruptions were irregular; by 2018 they had become highly predictable, nearly every 6 to 7 hours.

The name comes from the Hayden expedition of 1871, whose members had seen no larger geyser on their survey of the Yellowstone region. Visitors watch eruptions from the trail along the Grand Group, where Turban Geyser erupts every 17 to 22 minutes for about five minutes before Grand begins.

Grand erupts every 4 to 8 hours, and since 2018 nearly every interval is 6 to 7 hours. Watch Turban Geyser: Grand starts within 1 to 2 minutes of one of Turban's five-minute eruptions, which come every 17 to 22 minutes. After Grand stops, its pool stays empty for about five hours while refilling.

It ranks among the world's tallest predictable geysers and displays an unusual eruption pattern with several distinct bursts rather than a single continuous spray. This multi-peak behavior makes each eruption visually more complex than neighboring geysers.