Old Faithful Geyser

A geyser eruptions steam and water high into the area as people watch from boardwalks.
Eruption of Old Faithful Geyser viewed from Observation Point

NPS/Jim Peaco

Quick Facts

Old Faithful erupts more frequently than any of the other big geysers, although it is not the largest or most regular geyser in Yellowstone National Park. It is believed this regularity is in part due to no known connection with other hydrothermal features in the area.

Its average interval between eruptions is about 90 minutes, varying from 50 to 127 minutes. An eruption lasts 1.5 to 5 minutes and expels 3,700–8,400 gallons (14,000–32,000 l) of boiling water, and reaches a height of 106–184 feet (30–55 m). Old Faithful Geyser has an average temperate of 169.7°F (76.5°C), an average pH of 9, and an average conductivity of 1972 uS/cm.

Name Origin

Members of the Washburn expedition of 1870 named this geyser for its consistent performance. Although its average interval has lengthened, Old Faithful is as spectacular as it was a century ago.


The geyser is the centerpiece of the Old Faithful Historic District. The surrounding buildings are all set back from the geyser about the same distance: 1/8 mile (0.2 km). Only two buildings have been allowed to infringe upon this distance, established by Federal law: the Old Faithful Inn's east wing and the Old Faithful Lodge.

Visiting Tips

Yellowstone is a dangerous place filled with natural wonders unlike most anywhere else on Earth. As such, you cautious when explore thermal basins and around wildlife. You are responsible for your safety. Think safety, act safely.

  • Parking is limited in the summer months, especially 10 am-6 pm.
  • Use caution in hydrothermal areas.
    • Stay on boardwalks and designated trails.
    • Do not touch any hydrothermal water—it can severely burn you.
    • Never run, push, or shove.
    • Supervise children at all times.
    • Do not scratch hydrothermal mats.


Wheelchair-accessible walkways lead from all parking areas to Old Faithful Geyser, and from the Old Faithful Visitor Education Center to other hydrothermal features.

Upper Geyser Basin in Yellowstone National Park

Visit our keyboard shortcuts docs for details
4 minutes, 50 seconds

View of a summertime eruption of Old Faithful from the top of Old Faithful Inn.

Last updated: October 6, 2020