Kaumana Caves is a lava tube on the upper edge of Hilo, left by the eruption that came closer to destroying the town than any other. On 5 November 1880 Mauna Loa broke open on its northeast rift zone, near 11,000 feet. After the first fountains died away, a new vent began pouring out pahoehoe, the smooth, ropy kind of lava, and it built tubes that carried it far down the gentle slope toward the sea.
By late March 1881 the flow was about seven miles from Hilo, above Kaumana, and by early June about five. On 26 June it found the stream channels above town and sped up. A narrow branch crossed what is now Komohana Street in late July, and by 10 August every lobe had stopped, about a mile and a half from Hilo Bay, just north of where the University of Hawai‘i at Hilo stands today. Kaumana Cave was one of the main conduits feeding that advance. Princess Ruth Ke‘elikōlani came from Honolulu to help save the town, and when her carriage horse gave out on the Halai Hills, prisoners from the Hilo jail pulled her the rest of the way to a vantage point.
Today a collapsed skylight in a small park gives easy access to two of the tube's entrances. The tube has been surveyed at just over two miles, and parts of it, along with some of its entrances, run under private property, so stay in the public section. Visitors long ago broke off most of its lava stalactites and stalagmites as souvenirs; leave what is left.
Rock fell from the ceiling near the entrance on 23 September 2023. Nobody was hurt, but the caves stayed closed for nearly four months while the county had the site assessed with help from the Hawaiian Volcano Observatory and the University of Hawai‘i at Hilo, and they reopened in January 2024 with new signs on the risks. Bring a flashlight, sturdy shoes, gloves and a hard hat, and wear long sleeves and long pants.
Other places on the map within a couple of hours.
