In 1870, when members of the Washburn Expedition happened upon this Yellowstone geyser, they noted that the shape and structure of the crater resembled a castle’s tower. Since then, much of that stoic tower has gradually dissolved and eroded, although a 90‐foot-high (27-meter-high) column of boiling water still erupts with regular frequency.
On average, Castle Geyser has an eruption cycle in the vicinity of 10 to 12 hours, and eruptions will last for 20 minutes before the water changes to steam. Compared to nearby Old Faithful, however, predicting the timing of Castle Geyser can be more difficult. As one of the highlights of Upper Geyser Basin, Castle Geyser often features in guided tours of Yellowstone National Park, including day trips from Jackson Hole and Cody.
Things to Know Before You Go
- Castle Geyser is a must-see for visitors in Yellowstone’s Upper Geyser Basin.
- Plan to spend a couple hours at the geyser to maximize your chances of seeing it erupt.
- Don’t forget to bring sunglasses, sunscreen, and a hat.
- The geyser is wheelchair accessible via a paved trail and boardwalk from the Old Faithful area.
How to Get There
Castle Geyser is located in the Upper Geyser Basin of Yellowstone National Park. The drive from the west entrance—the closest entrance to the basin—takes about 45 minutes. On foot, the geyser is easily accessed by following the trail that leads from Old Faithful.
When to Get There
You’ll want to time your visit to Castle Geyser for when it’s predicted to erupt. Rangers at any of Yellowstone’s visitor centers should be able to offer an estimate; plan to arrive around 45 minutes early in case it goes off before the predicted time.
The Phases of a Castle Geyser Eruption
Unlike Old Faithful, when Castle Geyser erupts, it does so in two phases. For the first 20 minutes, the geyser spews out a column of water that can be seen over the trees from Old Faithful. Once the water phase finishes, the geyser belches out thick white steam for another 30 to 40 minutes. The thunderous sound of the steam eruption has been compared to the roar of an oncoming train.