Get unforgettable looks at the countryside utterly transformed by 20th-century eruptions of Kilauea Volcano on the Mauna Ulu Eruption Trail in Hawaii Volcanoes National Park. This self-guided interpretive path leads you through a young, lava-sculpted landscape full of insights into the shield-volcano processes that build the Big Island.
This 2.5-mile round-trip hike takes two or three hours to complete at a leisurely, reflective pace very much warranted by the fascinating setting.
It kicks off from the Mauna Ulu Trailhead, about a half-hour drive or so from the Kilauea Visitor Center via Crater Rim Drive and Chain of Craters Road. There’s a restroom here but no drinking water. Make sure you bring plenty of H2O to stay hydrated on this waterless walkabout. Sun protection is definitely needed, too, as is raingear in case of wet weather.
This is mostly a very easy hike over gentle terrain. We say “mostly,” because the end-of-trail payoff is a quarter-mile, 210-foot climb up the Puu Huluhulu (Shaggy Hill) cinder-and-spatter cone. That’s the most strenuous part of the undertaking, but switchbacks ease the ascent.
You’ll be walking through the upper part of Kilauea’s volatile East Rift Zone, which has seen much of the volcano’s eruptive activity in recent decades. Part of this trail follows the former route of Chain of Craters Road. A lineup of more than a dozen pit craters along the Rift Zone gave the road its name.
In 1969, though, the Mauna Ulu eruption set about changing the look of the regional real estate. A vent opened up that began spewing towering lava fountains, some geysering taller than the Empire State Building.
Over the course of five years, this eruption built up the brand-new, 400-foot-tall Mauna Ulu lava shield and flooded the surroundings with lava. Mauna Ulu lava cascaded into five local pit craters—Hiiaka, Pauahi, Aloi, Alae, and Makaopuhi—filling some to the brim. Forests and grasslands were scorched, roadways obliterated. Some of the lava reached the ocean in dramatic, steam-billowing fashion.
You’ll definitely want to walk this path with the official National Park Service trail guide to refer to. You can pick up a hard copy of the Mauna Ulu Eruption Trail Guide at the visitor center or download it from the park’s website.
Along the hike, you’ll tread over smooth, ropy pahoehoe lava and craggier, sharper aa lava. Look for cinders, lava foam, the fine lava threads called “Pele’s hair,” and the smooth lava-drops known as “Pele’s tears.”
Crusted-over trailside lumps and pillars—“lava trees”—show where lava molds encased burned trees. But the route also visits a kipuka: an island of forest perched on a higher, older lava flow that survived the eruption. This pocket of trees then served as a seed reservoir to help revegetate the Mauna Ulu lava flows, a slow process still ongoing.
Landmarks near and far demonstrate the workings of Pele, the Hawaiian volcanic goddess. Wooded Puu Huluhulu, half a millennium or so older than Mauna Ulu, is now overshadowed by the 1969-1974 lava shield. To the east, you can pick out the cone of Puu Oo, a vent that erupted spectacularly from 1983 to 2018. Clear-day views give you looks at the enormous Mauna Loa and Mauna Kea shield volcanoes: older cousins and neighbors of Kilauea. (Well, more than just neighbors: Kilauea Volcano is growing on the side of Mauna Loa.) You can also see out to the Pacific, the realm of the ocean goddess (Pele’s sister).
The views are farthest-reaching from the top of Puu Huluhulu, the turnaround point for this hike. This cone’s crater shelters native vegetation that in the surrounding area is vulnerable to the ravages of feral pigs.
A few hours happily spent exploring the Mauna Ulu Eruption Trail provide a memorable introduction to the Kilauea East Rift Zone, one of the most dramatic—and changeable—corners of the Hawaiian Islands.
Where the trail up Puu Huluhulu turns northeast, another pathway leads east: the Napau Trail. This longer hike treks into the backcountry to end at Napau Crater and Puu Oo. Even if you aren’t down for that lengthy (about 12-mile) dayhike or backpack, you might consider walking the Napau just as far as the great Makaopuhi Crater. This biggest of the Kilauea pit craters is a dramatic sight, and tacking it on makes for only about a 4.5-mile round-trip hike.