- Pierce County, located in southwestern Washington abutting Puget Sound, encompasses an extremely wide range of elevations: from sea level on Puget Sound to 14,410 at the summit of Mount Rainier. The entire footprint of Mount Rainier, an active Cascade volcano encased in more than 35 square miles of snow and glacial ice, lies within the county’s boundaries. Pierce County comprises 1,675 square miles, placing it 23rd in size among Washington’s 39 counties…