What is the name of the world's longest lava tube, located in Hawaii?

The world's longest lava tube is Kazumura Cave, a vast volcanic cave system on Hawaii's Big Island. It lies on the eastern slope of Kilauea and follows passages formed by ancient basaltic lava flows.

Kazumura Cave has been surveyed at roughly 40.7 miles (65.5 kilometers), making it not only the longest known lava tube but also one of the longest cave systems of any type. Its passages descend about 3,614 feet (1,101 meters), giving it the distinction of being exceptionally deep as well as long.

The cave formed in the Ailā'au lava flow, which originated near Kilauea Iki roughly 500 years ago. Many passages once considered separate caves were later connected through exploration and surveying, producing the modern cave system. More than 100 entrances are known, most on private property.

Kazumura is not a typical tourist cave. Its passages include tight crawls, unstable breakdown areas, and difficult sections, while its ecosystem supports endemic Hawaiian cave species. Thurston Lava Tube, another famous Hawaii attraction, is much shorter and is not the world's longest.