Uinkaret volcanic field, Volcanic field in northwestern Arizona, United States

Uinkaret volcanic field is a broad expanse of volcanic cones and basaltic lava flows in northwestern Arizona, sitting between the Toroweap and Hurricane faults near the Grand Canyon. The ground across the field is dark and broken, shaped by layers of hardened lava that cover much of the surface.

Hundreds of thousands of years ago, lava erupting from this field repeatedly flowed into the Grand Canyon and blocked the Colorado River, forming natural dams that altered the river's path. Over time, the river cut through those barriers and left behind the broken terrain that defines the area today.

The area holds traces of early settlement from a time when people lived here while volcanic activity was still ongoing around them. Pottery fragments found across the terrain tell of daily life carried out on ground that was still geologically young.

The field sits in a remote part of northwestern Arizona and is reached by unpaved roads, so a high-clearance vehicle is strongly advisable. The volcanic surface is rough and uneven underfoot, making sturdy footwear necessary for any time spent walking across the terrain.

Lava Falls, widely considered the fiercest rapids on the Colorado River through the Grand Canyon, owes its character to deposits that came directly from this field. Standing at the rim above them, you can see how the old lava rock still narrows the riverbed and drives the water into a fury.