The latest eruption spewed out nearly 240 cubic miles of debris. The magmatic heat powering those eruptions still powers the park's famous geysers, hot springs, fumaroles, and mud pots . Rugged mountains flank the park's volcanic plateau, rewarding both eye and spirit. One of the main routes to Old Faithful is from the south via Jackson, Wyoming, and the South Entrance. The park road crosses the Continental Divide three times.
Waters flow east of the divide to the Atlantic, or west to the Pacific.
Sampling the world's largest concentration of geysers, you follow the beautiful Firehole and Gibbon rivers. A visitor center at Old Faithful and a museum at Norris tell aspects of the park story. Old Faithful Old Faithful Geyser is the world's best-known geyser. Its eruption intervals have long varied around an average of 65 minutes, ranging from 30 to 120 minutes. Recent earthquakes have lengthened the average interval to 78 minutes.