ʻĀinapō Trail

ʻĀinapō is a remote out-and-back from the trailhead at the end of ʻĀinapō Road to Mauna Loa Summit Cabin. The trail itself is about 20.4 miles round trip and climbs roughly 7,600 feet to a cabin at 13,250 feet. Most hikers break the climb at ʻĀinapō Cabin at Halewai, 2.7 miles in, before taking the difficult 7.5-mile upper leg. It’s a multi-day backcountry trip for experienced hikers, not a park day walk. The high cabin is below Mauna Loa’s actual 13,681-foot summit; this route ends at the cabin.

Reach the start by driving eight miles up rough, infrequently maintained ʻĀinapō Road: 5.7 miles cross Kapāpala Ranch and another 2.3 miles continue through the forest reserve. Arrange gate access with the ranch ahead of time, keep to the signed access road, and use a high-clearance four-wheel-drive vehicle. Parking at the trailhead is limited. Walking in from Highway 11 adds about eight miles each way, outside the trail distance above.

The first 2.7 miles to Halewai are challenging; the cabin sits at 7,750 feet. The next 7.5 miles are difficult and steep. The route climbs from forest with native plants into stark volcanic terrain, with rough, jagged and often loose lava underfoot. Cairns mark the route, but they can be hard to follow in mist or other low visibility. Don’t set out unless you’re comfortable with remote route-finding and a long, demanding climb.

Halewai is the usual overnight stop before the upper climb. Mauna Loa Summit Cabin has basic shelter, sleeping bunks, a cooking area, a pit toilet and rain-catchment water. Treat the water and confirm its availability before relying on it. Overnight stays at Halewai and the summit cabin require separate permits from the State and the National Park Service.

The route reaches 13,250 feet, where altitude sickness is a serious risk. High winds, freezing nights, snow, driving rain and whiteouts can occur in any season. Sharp, loose lava makes falls painful, and cairns can disappear in poor visibility. Pets aren’t allowed on the park trail. Anyone who has scuba-dived in the previous 24 hours should postpone the ascent.