Where Are the Oldest Mountains in the World?

The Appalachian Mountains of eastern North America are widely considered the oldest major mountain range on Earth. Their formation began over 480 million years ago (Ordovician Period) during the Taconic orogeny, followed by the Acadian, Alleghenian, and other collisions as ancestral continents (Laurentia, Gondwana, Avalonia) converged to form Pangaea.

Key facts:

• Extent: ~1,500 miles (2,400 km) from Alabama to Newfoundland/Labrador.
• Highest Peak: Mount Mitchell, NC (6,684 ft / 2,037 m).
• Age vs. Height: Once Himalayan-scale, hundreds of millions of years of erosion have worn them to their current rounded, forested ridges.
• Geologic Legacy: Exposed deep crustal rocks reveal the roots of ancient collision zones; coal, iron, and gas deposits fueled US industrialization.

Older individual rock formations exist (e.g., Canadian Shield, Greenland, Pilbara Craton >3.5 Ga), but as a continuous mountain system, the Appalachians are the senior range.