Large Physiographic Regions of the United States

Major Landform Provinces

1. The Great Plains

Broad expanse (1M+ mi²) from Rockies to Mississippi River; 10 states. Semi-arid west to humid east. Wheat, corn, cattle, energy. Cities: Denver, Omaha, Kansas City, Oklahoma City.

2. The Rocky Mountains

Cordilleran backbone (Canada to NM); 200k+ mi²; peaks >14,000 ft. Headwaters of Colorado, Rio Grande, Missouri, Columbia. Recreation, mining, forests.

3. The Colorado Plateau

130k mi² of layered sedimentary rock (UT, AZ, CO, NM). Grand Canyon, Bryce, Zion, Arches. High desert, canyons, monoliths. Tourism, uranium, grazing.

4. The Great Basin

200k mi² of internal drainage (NV, UT, ID, OR, CA). Basin-and-range topography; Mojave, Sonoran deserts; Sierra Nevada west edge. Endemic species, mining, renewables.

5. The Columbia Plateau

100k mi² of flood basalts (WA, OR, ID, MT). Channeled Scablands, Palouse hills. Wheat, apples, hydro (Columbia River dams). Cities: Spokane, Tri-Cities, Yakima.

These regions define climate, ecology, economy, and culture across the western two-thirds of the US.