Old Faithful is Yellowstone National Park’s most famous and easiest accessible geyser in the park. Discovered in 1870 by the Washburn Expedition, Old Faithful geyser was named for its frequent and somewhat predictable eruptions, which number more than a million since Yellowstone became the world’s first national park in 1872. 
 
The geyser-viewing area is visitor-friendly with bench seating, a large parking lot, and a ranger station that tracks the time, height and length of an eruption to predict the next eruption. The mathematical average between eruptions is currently 74 minutes, but it doesn't like to act average! Intervals can range from 60-110 minutes.