Upper Geyser Basin and Old Faithful

Upper Geyser Basin holds Old Faithful, making it one of the most developed and popular spots in the park. You can find the Old Faithful Inn, one of the few attractions inside the park that is manmade. The basin holds hundreds of other geysers and hot springs other than the world-famous one. The majority of the worlds active geysers are in the Upper Geyser Basin. During the summer, rangers forecast the eruption times of five geysers here, Old Faithful, Castle, Grand, Daisy and Riverside. Only four other locations in the world have large concentrations of geysers, Russia (Kamchatka), Chile, New Zealand and Iceland.

The Upper Geyser Basin, molten rock, or magma, from this volcano may be as close as 3 to 8 miles below your feet. Magma provides the first key ingredient for creating thermal features. Rain and snow supply the second ingredient, water. The water seeps down several thousand feet below the surface where it is heated. Underground cracks and faults from the third ingredient, a natural plumbing system. Super-heated water rises through the plumbing to produce hot springs and geysers.

Old Faithful erupts more frequently than any of the other big geysers, although it is not the largest or most regular geyser in the park. After watching Old Faithful erupt, be sure to take a walk on the trails throughout the basin. There are small and large loop trips available.