Old Faithful area Yellowstone NP

Old Faithful was named by the first official expedition to Yellowstone, the Washburn Expedition of 1870. They were impressed by its size and frequency. Old Faithful erupts every 35 to 120 minutes for 1 1/2 to 5 minutes. Its maximum height ranges from 90 to 184 feet.

The amount of water expelled per eruption is 3,700-8,400 gallons depending on the length of the eruption.

Old Faithful's "sister", Castle Geyser, is located within an easy walk & view of Old Faithful.  Both geysers were going off at the same time the day we were there.

Historic Old Faithful Inn was opened in 1904 and built by the Yellowstone Company which was affiliated with the Great Northern Railway.