Hell’s Half Acre — Main Vent Trail
Idaho Falls / Twenty Mile Trail, Idaho
Activity
Hiking / Volcanic
Distance
9 mi round trip
Elevation gain
~350 ft
Route
Out & back
The adventure
Follow the primitive lava route 4.5 miles to the main vent and return. The route reaches the source vent.
Leave Twenty Mile Trailhead, follow the pole-marked route 4.5 miles to the main vent, reach it safely and return to the trailhead. Sturdy footwear matters. Heat and exposure are major factors.
ONCE YOU’RE THERE Turn at the signed Lava Trail road near Highway 20 mile marker 287, stay left at the fork and drive the final quarter-mile to the trailhead. Follow pole markers across the lava and retrace them.
LOCAL INTEL Markers are the navigation line.
FEES, PERMITS & ACCESS No mandatory entrance, parking, access, permit, reservation, or similar fee is required to complete this Adventure as routed.
What to expect
- Follow the primitive lava route 4.5 miles to the main vent and return.
- Turn at the signed Lava Trail road near Highway 20 mile marker 287, stay left at the fork and drive the final quarter-mile to the trailhead. Follow pole markers across the lava and retrace them.
Good to know
- MAIN VENT
- The route reaches the source vent.
- SHARP LAVA
- Sturdy footwear matters.
- NO SHADE
- Heat and exposure are major factors.
- FOLLOW THE POLES
- Markers are the navigation line.
- FIND A KIPUKA
- Spot an island of older soil and vegetation without leaving the route.
- Fee
- Free — no required entrance or parking fee.
- Entrance fee
- No mandatory entrance, parking, access, permit, reservation, or similar fee is required to complete this Adventure as routed.
- Dogs
- unknown.
Photos
More adventures nearby
Blackfoot Rest Area · Blackfoot, Idaho
Hell’s Half Acre Interpretive TrailHiking · Easy · ~20 mi away
