Henry's Fork Caldera Crater
Volcanic caldera forming Yellowstone hotspot's eastern volcanic complex
A volcanic caldera in eastern Idaho's Island Park area, Henry's Fork Caldera attracts geology enthusiasts and anglers who come for the Henry's Fork River, fly-fishing and nearby geothermal features.
Henry's Fork Caldera at a Glance#
Website: https://www.fs.usda.gov/
Admission: Entrance to surrounding public lands generally free; commercial guided tours vary
About Henry's Fork Caldera#
Henry’s Fork Caldera is a volcanic caldera in eastern Idaho associated with the Yellowstone hotspot track. It is a geologically significant feature within the northern Rocky Mountain volcanic province.
The caldera formed during a major volcanic event in the Pleistocene related to the Yellowstone hotspot; subsequent eruptions and tectonic activity have shaped the present landscape. It is one of several nested or adjacent calderas in the region created as the hotspot migrated.
The feature lies in eastern Idaho near Island Park and Henrys Lake, within a region of high plateaus and forested mountain terrain west of the Yellowstone Plateau.
- Geologic context: Formed by volcanic activity associated with the Yellowstone hotspot, making it part of a chain of calderas across the northern Rocky Mountains.
- Landscape: Surrounding terrain includes high plateau, lakes, and geothermal-influenced landscapes that attract geological and ecological study.
How to Get to Henry's Fork Caldera#
The caldera is accessed via roads off Idaho highways serving the Island Park and Yellowstone regions. The nearest towns with services include Ashton and Island Park; many visitors arrive from West Yellowstone. Use US Forest Service maps and local guides for trailheads and backcountry planning.
Tips for Visiting Henry's Fork Caldera#
- Visit early morning for geothermal steam and wildlife sightings.
- Best visited with a map and local guidance if hiking - volcanic terrain can be disorienting.
- Bring layers; high‑elevation mornings are cool even in summer.
Best Time to Visit Henry's Fork Caldera#
Late spring through early autumn is the best window for visiting the Henry's Fork Caldera and its high‑country features.
Weather & Climate near Henry's Fork Caldera#
Henry's Fork Caldera's climate is classified as Warm-Summer Continental (Dry Summer) - Warm-Summer Continental (Dry Summer) climate with mild summers (peaking in July) and freezing winters (coldest in January). Temperatures range from -16°C to 26°C. Moderate rainfall (668 mm/year).
| Month | Comfort | Temp | Feels | Rain | Sky | Humidity | Wind | UV | Daylight |
|---|---|---|---|---|---|---|---|---|---|
| January | - | -16° - -4° | -15° | 85 mm | - | - | 3.1 m/s | - | - |
| February | - | -14° - 0° | -12° | 65 mm | - | - | 3.1 m/s | - | - |
| March | - | -10° - 4° | -8° | 60 mm | - | - | 3.5 m/s | - | - |
| April | - | -5° - 9° | -2° | 49 mm | - | - | 3.6 m/s | - | - |
| May | - | 0° - 15° | 5° | 60 mm | - | - | 3.7 m/s | - | - |
| June | - | 4° - 21° | 12° | 56 mm | - | - | 3.5 m/s | - | - |
| July | - | 6° - 26° | 16° | 34 mm | - | - | 3.2 m/s | - | - |
| August | - | 6° - 26° | 16° | 35 mm | - | - | 3.1 m/s | - | - |
| September | - | 1° - 21° | 11° | 41 mm | - | - | 3.1 m/s | - | - |
| October | - | -4° - 13° | 2° | 41 mm | - | - | 3.2 m/s | - | - |
| November | - | -9° - 3° | -8° | 64 mm | - | - | 3.3 m/s | - | - |
| December | - | -15° - -3° | -15° | 78 mm | - | - | 3.1 m/s | - | - |