Plate tectonics—the shifting of large, relatively thin segments of Earth’s crust—and stream erosion have done the most to create Arizona’s spectacular topography… See more

To Arizona’s two major physiographic divisions, the Colorado Plateau and the Basin and Range … See more

Virtually all of Arizona lies within the Colorado River drainage system. The Gila River, with its major feeder streams—the Salt and the Verde—is by far the Colorado’s … See more