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. Old Faithful can vary in height from 100-180 feet with an average near 130-140 feet. Eruptions normally last between 1.5 to 5 minutes.

Here is a sequence of images depicting a dormant Old Faithful to eruption and then cool down ……