Valles Caldera National Preserve

Highway 4 climbs west out of the ponderosa forest beyond Los Alamos and comes out suddenly on the rim of the Valle Grande, a sweep of grass running miles to the north with Redondo Peak rising beyond it. This is the floor of the Valles Caldera, about thirteen miles wide, the hollow left when the Jemez volcano erupted and collapsed in on itself about 1.25 million years ago. Redondo, about 11,250 feet, is a resurgent dome, ground pushed back up from below after the collapse.

People came here for at least eleven thousand years to hunt and to gather obsidian, and points of Jemez obsidian have turned up from the northern plains to Mexico. Redondo Peak is sacred to Jemez and other pueblos, and its summit is closed to hikers.

The caldera's private century began with a quarrel over Las Vegas, a hundred miles east. Luis María Cabeza de Baca's heirs and the town of Las Vegas claimed the same grant, and in 1860 Congress settled it by letting the heirs choose an equal acreage of vacant land elsewhere, in up to five squares. Their first choice, Baca Location No. 1, took in the Valle Grande. For 140 years it was sheep range, cattle ranch and logging country. In 2000 the government bought the ranch, about 89,000 acres, for $101 million and handed it to a trust expected to pay its own way by 2015; the same law transferred some 5,000 acres to Santa Clara Pueblo. The trust never paid its way, and in 2015 the National Park Service took the preserve over.

The entrance road leaves Highway 4 for the Valle Grande staging area and the old ranch buildings. Elk graze the valleys at dawn and dusk. Much of the backcountry is open only by permit or on set days.