The Uinkaret volcanic field is an area of monogenetic volcanoes in northwestern Arizona, United States, located on the north rim of the Grand Canyon. Lava flows from the Uinkaret volcanic field that have cascaded down into the Grand Canyon, damming the Colorado River, have been used to date the canyon's carving. One of these cascades is today's Lava Falls. , below Lava Falls on the Colorado River, is "at all water levels, the most severe rapid in Grand Canyon."