Which mountain range in North America is the oldest?

The Appalachian Mountains are generally regarded as the oldest major mountain range in North America.

The Appalachians stretch about 2,050 miles from Newfoundland in Canada to central Alabama in the United States. Their rocks preserve evidence of multiple mountain-building episodes, some beginning more than a billion years ago, long before the Rocky Mountains formed.

The range’s present structure was shaped especially by collisions between ancient continental landmasses during the Paleozoic Era. These events helped assemble the supercontinent Pangaea and produced folded, faulted mountains that were once far taller than the rounded ridges seen today.

Weathering and erosion have worn the Appalachians down over immense spans of time. Mount Mitchell in North Carolina, at 6,684 feet, is their highest point and the highest summit east of the Mississippi River. The Rockies are younger and generally higher, which is why age and elevation should not be confused in this comparison.