Henry's Fork Caldera

Henry's Fork Caldera spans 37 kilometers wide and 29 kilometers long, forming a circular structure within the larger Island Park Caldera in eastern Idaho.

The caldera emerged from a massive volcanic eruption 1.3 million years ago, expelling 280 cubic kilometers of ash that spread across Wyoming, Colorado, Nebraska, and Kansas.

Scientists and geologists frequently visit this location to study volcanic processes and monitor the ongoing activity of the Yellowstone hotspot system.

Visitors can access multiple outdoor activities throughout the caldera area, including Nordic skiing, fishing, snowmobiling, and wildlife observation at Harriman State Park.

This caldera remains the only visible formation among numerous calderas created by the Yellowstone hotspot, featuring the Henry's Fork of Snake River flowing through its center.

Location: Fremont County

Elevation above the sea: 2,805 m

GPS coordinates: 44.33000,-111.33000

Latest update: March 8, 2025 19:30