premise: Pierce County, Washington is the location of the highest mountain of the Cascade Range of the Pacific Northwest.
hypothesis: The Cascade Range or Cascades is a major mountain range of western North America , extending from southern British Columbia through Washington and Oregon to Northern California . Mount Rainier ( pronounced : [ reɪˈnɪər ] ) , Mount Tacoma , or Mount Tahoma is the highest mountain of the Cascade Range of the Pacific Northwest , and the highest mountain in the U.S. state of Washington . Pierce County, Washington . Pierce County is notable for being home to Mount Rainier , the tallest mountain and a volcano in the Cascade Range .