Separated from the gaping Kilauea Caldera by the Byron Ledge, Kilauea Iki in Hawaii Volcanoes National Park well earns its name: “Little Kilauea.” This pit crater produced a truly sensational eruption back in 1959, and the extremely popular Kilauea Iki Trail gives you a firsthand look at the surreal remnants.
This hike is a 3.3-mile loop consisting of the Kilauea Iki Trail proper and part of the Crater Rim Trail. With about 400 feet of elevation change, it’s a moderately challenging two- to three-hour trek involving climbing down and back up the walls of the pit crater. While portions of this hike are shaded, the centerpiece—the walk across the crater—is most definitely not. Try to tackle this trail early or late in the day, or do it under overcast conditions if you can.
You can access this hike from two spots along the national park’s Crater Rim Drive: the Kilauea Iki Overlook and the Thurston Lava Tube parking area. We’ll use the latter (which has restrooms) for this description. And we’ll present it as if you were hiking counterclockwise, though you can also do the loop in the other direction. This route sees you on the Crater Rim Trail first, then traversing the crater floor on the Kilauea Iki Trail itself.
Your hike proceeds along the rainforested eastern and northern rim of Kilauea Iki Crater. From the Kilauea Iki Overlook that you soon reach, you’ll enjoy a nice view of the pit crater—including the path you’ll be taking across the floor—as well as Kilauea Caldera and, in clear weather, the huge loom of Mauna Loa beyond.
In late 1959, following weeks of earthquake swarms, Kilauea Iki began erupting in a dramatic fashion. A fissure opened up and vents along it spewed fountains of lava, eventually merging into one main vent. More than a dozen fountaining eruptions occurred, filling the pit crater with a lava lake. One of these eruptive episodes, on December 17th of that year, shot up a 1,900-foot-tall lava fountain: the tallest ever recorded in Hawaii.
As the lava lake rose up above the main vent, the fountains stopped gushing. The lake would drain through the vent in a rapid, messy, whirlpooling fashion. The Kilauea Iki eruption of 1959 continued cycling for 36 days.
After hiking along the northern crater rim, ignoring a couple of trails that branch off to the Volcano Visitor Center, you’ll turn south and then east to drop into the crater. Kilauea Iki was some 800 feet deep (about twice the current depth) and forested before its 1959 eruption. The modern floor represents the crusted-over surface of the lava lake, which is now completely solid but still hot deep within.
The beaten-down path across the crater floor is marked by cairns. You’ll pass close to a cinder-and-spatter cone formed during the 1959 event: Puu Puai, the “gushing hill.” The main vent is visible near the cone’s base, choked with rocks. The prominent black ledge around the crater is something like a “bathtub ring,” marking clodded lava stuck to the walls at the highest level the lake reached. (It’s technically known as a lava subsidence terrace.)
The floor of the crater steams from cracks due to rainwater that percolates downward and then boils off due to the deep heat. Needless to say, you should stick to the main path: The crater’s cracks can be deep, and there’s the potential for being scalded.
Scrubby ohia trees, ohelo ai shrubs, ferns, and other plants pepper the crater floor, growing from windblown seeds lodged in lava cracks. They suggest the future forest that could again blanket Kilauea Iki.
After traversing the crater to the southeast, you’ll climb up the eastern wall through an ohia forest that persisted above the molten-pool zone. The shade’s welcome after your (utterly unforgettable) walk across the lava lake!
Your eyes will be drawn to the crater floor and rim as you trek along. But occasionally look up into the sky above: You might spot white-tailed tropicbirds or even a Hawaiian hawk drifting overhead.