When Castle Geyser is erupting, it is one of the more distinguishing features of the Upper Geyser Basin landscape in Yellowstone National Park. If you follow the boardwalk from Old Faithful up to the Chromatic and Beauty Pools , this attraction is situated across the Firehole River.
It erupts every 11 to 13 hours and reaches 75 feet in height. The eruption lasts about 20 minutes. The large cone means that it's very old. Thousands of years of scalding water has deposited silica in a heaping pile. By comparison, the Old Faithful is only a few hundred years old.
The geothermal feature has dramatically changed its surroundings by flooding the area with hot, silica-rich water. It erupts twice per day.