A desert state through and through, Arizona is a land primarily of intermittent rivers with the notable exceptions of the Gila and, in the state’s northwest corner, one of the most extraordinary stretches of river on Earth, the Grand Canyon of the Colorado River.
The rivers of California sustain some of the most extraordinary and biodiverse landscapes on the planet, including the Klamath-Siskiyou, the Sierra Nevada, the Central Valley, Mediterranean California and the Southwest.
The Colorado, Rio Grande, Arkansas and Platte all rise in the Rocky Mountains, which form a massive north-south backbone across the state, separating the Great Plains of the east from the desert and red-rock canyons of the Colorado Plateau to the west.
The Idaho landscape is dominated by the towering Middle and Northern Rockies, which send nearly all of the state’s rivers to the Columbia Plateau and into the Snake River.
In Montana, swift, wild rivers rush down the western flanks of the Northern and Southern Rockies, while the streams of eastern Montana begin in the Rockies but slow to long, gentle meanders as they cross the vast grasslands of the Great Plains.
Lying squarely in the rain shadow of the towering Sierra Nevada, the West’s driest state is nearly all desert. Nevada’s rivers rarely make their way to the ocean, flowing instead into low basins between thin mountain ranges and evaporating into the desert air.
Great rivers like the Colorado, Green, San Juan and Dolores flow from the peaks of the Southern Rockies, which bisect Utah north to south, separating the Great Basin of the west from the Colorado Plateau to the east.
Washington’s rivers nourish wildly different landscapes, from the Northern Rockies, to the arid expanses of the Columbia Plateau, to some of the wettest places in North America along the rain-pounded Pacific Coast.