Jornada del Muerto means "Dead Man's Route" in Spanish,[2] referring to the desolate colonial era trail from New Spain through this Malpaís region.

The main volcano vent is located slightly to the east of the center of the lava flows, rising about 150 feet (46 m) in a broad but conspicuous cone about a mile (1.6 km) in diameter.

The volcano erupted about 760,000 years ago in a series of basaltic flows.

It produced a slow and viscous ʻaʻā lava volcanic field which has a very rough and uneven surface, making travel across it extremely difficult and hazardous; also time consuming.

Currently the flow forms the east bank of the Rio Grande from Fra Cristóbal north to Fort Craig, but at the time of eruption it temporarily dammed the Rio Grande.