Drive south until the road literally ends at La Perouse Bay, and Maui changes character completely. This is the island's youngest lava — a black, cracked flow a couple of centuries old — and threading across it is the Hoapili Trail, a stretch of the old King's Highway built in the 1820s under Governor Hoapili. It is the harshest, emptiest, most atmospheric walk on the island.
What you are walking on
The lava under your boots came from Haleakala's final eruption, which flowed down this coastline only about two hundred years ago — the mountain's goodbye, for now. Nothing here has softened yet: the flow is still sharp, black and nearly bare, which is exactly what makes the walk extraordinary.
The trail itself is the extraordinary part. The King's Highway once circled the entire island, and this section was rebuilt in the 1820s under Governor Hoapili — a raised bed of crushed and fitted lava stones running dead straight across country too rough for anything else. You are hiking a two-hundred-year-old piece of civil engineering.
From the La Perouse Bay lot, the route hugs the shore past tide pools and coves before cutting inland across the open flow toward Kanaio. Most walkers go out an hour or two and turn around — the character of the place lands within the first two miles.