Largest and Second-Largest U.S. Mountain Ranges: Rockies and Appalachians

The two most extensive mountain systems in the United States are:

1. Rocky Mountains — Largest. Stretches ~3,000 miles (4,800 km) from northern British Columbia, Canada, to New Mexico. Highest peak: Mount Elbert, CO (14,440 ft / 4,401 m). Includes major subranges: Front Range, Sawatch, San Juans, Tetons, Wind Rivers, Bitterroots.
2. Appalachian Mountains — Second largest. Extends ~2,000 miles from Newfoundland, Canada, to central Alabama. Highest peak: Mount Mitchell, NC (6,684 ft / 2,037 m). Older, more eroded, characterized by parallel ridges and valleys.

Other significant ranges (Sierra Nevada, Cascades, Alaska Range, Brooks Range) are smaller in areal extent but contain higher individual peaks (Denali, 20,310 ft). The Rockies and Appalachians define the continent's broad physiographic structure.