Puʻu o Lokuana

Puʻu o Lokuana is a cinder cone in the Kahuku Unit, climbed on a short loop through grass and a historic quarry to a summit with views over Kahuku and the Kaʻū coast. It suits a quick walk when you’re over by the unit, especially if geology or ranch history interests you; the climb is steep and uneven, so don’t expect a flat viewpoint stroll. The short loop is 0.4 mile with 130 feet of elevation change; allow 30 to 45 minutes. A longer 2-mile loop adds old ranch roads, pasture, an airstrip and the 1868 lava flow. Kahuku has a limited opening schedule, so check the park’s current hours before driving over. Pets aren’t allowed on this hike.

The cinders are red because iron in them oxidized. Quarrying removed nearly 100 feet of the hill, and that material ended up beneath gardens, homes and roads around Kaʻū. The name Puʻu o Lokuana refers to a heavy fall of cinder from lava fountains, which is a good description of the place you’re walking through.

From the summit, the view runs over green Kahuku to the Kaʻū coastline. For a photo, include the red quarry cut with the pasture and coast beyond it; that gives the picture both the cone’s unusual color and its wider setting.

During World War II, the military used the hill for a secret radar station. Marines watched radar screens from a dark room cut into the red cinders, and the old tower’s foundation blocks remain on the hill. It’s an unexpected piece of the story at a place that can look like a simple grassy summit from below.

The 2-mile loop follows old ranch roads through pasture, crosses the 1868 lava flow and reaches an old airstrip. Look for tiny green olivine crystals along the airstrip and lava tree molds on the route. Kahuku was a cattle ranch by 1861, and cattle production continued here for more than 150 years; the longer route makes that ranching landscape easier to picture alongside the volcanic terrain.