If you’re looking for a hike in Maui’s remarkable Haleakala National Park that’s on the quiet, lightly trammeled end of the spectrum, the Supply Trail should be on your radar. This trek through Haleakala Volcano’s subalpine shrublands rewards with long-range views, especially on clear days, and up-close looks at unique local ecology.
The Supply Trail is a 4.6-mile round-trip route connecting the Hosmer Grove Campground road at the northwest end with the Halemauu Trail to the southeast. It’s a moderately strenuous hike gaining close to 1,000 feet of elevation, though switchbacks ease the climb.
The Supply trailhead isn’t always marked, and the start of the trail is hard to discern. The trailhead is on the south side of the road to Hosmer Grove Campground, about midway between the Haleakala Highway and the campground. There’s a pull-off here and, at least sometimes, a sign.
You won’t find anything in the way of services at the trailhead, but they’re not far away. The Hosmer Grove Campground has restrooms and drinking water, as does the Haleakala National Park Headquarters Visitor Center less than a mile south of the Hosmer Grove turnoff.
Though you may not initially see the path, you should be able to pick it out after walking a short way south of the pull-off into the grassy expanse. From there on out, the Supply Trail is easy enough to follow. It proceeds generally southward uphill, turns southeastward to cross a large gully at about a third of a mile, and then heads east.
You’re crossing through the dense subalpine shrubland that covers large areas of the middle and upper elevations of Haleakala. This stunted tangle includes native shrubs such as ohelo, mamane, pukiawe, pilo, and kupaoa as well as various ferns. Birdlife is rich here and includes the Hawaiian goose, or nene, which is often seen along the Supply Trail.
The trail skirts the highway again in the vicinity of water towers and ascends further toward the Halemauu Trail, traversing more plunging gullies. These ravines drain into or parallel the great Koolau Gap forming the northwestern breach of Haleakala Crater. Depending on the weather, you may be hiking through blowing mist or enjoying far-reaching views from this high country. Often you’ll find yourself above the trade-wind inversion’s stratus cloud deck that frequently builds against Haleakala as the day proceeds.
The junction with the Halemauu Trail marks the southern terminus of the Supply Trail. But you definitely should consider walking a short way east on the Halemauu to feast on more scenery. Only a quarter-mile or so down the Halemauu Trail, you’ll start goggling at prospects over Haleakala Crater. Continue to the spectacular narrows called the “Rainbow Bridge” for breathtaking crater vistas.
The huge “crater” below is not a true volcanic crater, in fact. Rather, it’s an erosional basin formed by valley-cutting and slumping. If you want to push yourself, you can begin the switchbacking descent from the Rainbow Bridge down into Haleakala Crater. But that’d end up being quite a demanding hike, given the climb back out and then the return to the trailhead. The panoramic views that a short walk along the Halemauu Trail delivers will be a sufficient reward for most Supply Trail hikers.
The Supply Trail shows off the beauty of Haleakala National Park’s high shrublands and its sprawling East Maui scenery. And you’ll the trail mostly or entirely to yourself!
The Supply Trail’s tread is quite rocky in places. Be especially mindful of your footing on the descent back to the trailhead.