Perhaps the most well-known feature of the park, Old Faithful was the first geyser in Yellowstone National Park to be named during the first official exploration of the region, the Washburn Expedition of 1870.

While not the largest geyser in Yellowstone, this cone geyser is notable for the frequency and reliability of eruptions with an interval of approximately 90 minutes. Although the interval has increased slightly over the years, with eruptions ranging between 45 to 125 minutes apart, the geology underlying the geyser is not connected to any other thermal features, making the prediction of eruptions easier to calculate.

The eruptions can propel nearly 8,500 gallons (32,176 liters) of super-heated water and steam to an average height of 145 feet (45 meters) into the air.

Accessible year-round. Yellowstone National Park accessibility restrictions and hours apply.

Fees: Yellowstone National Park fees apply.