Mount Rainier

Mount Rainier is Washington’s highest peak, a large active stratovolcano in the Cascade Range that dominates the Seattle-Tacoma skyline and holds deep Indigenous significance, reflected in many long-used native names. Built from lava, debris flows, and pyroclastic material, its present cone is more than 500,000 years old. A massive collapse about 5,000 years ago unleashed the Osceola Mudflow, lowering the summit and spreading debris far into the Puget Sound lowlands before later eruptions rebuilt the cone. With extensive glaciers, crater caves, and exceptional climbing appeal, it is also closely monitored because lahars and eruptions threaten nearby populated valleys.

Ashford, Washington · United States