Pierce County is a county in the U.S. state of Washington.  The county seat and largest city is Tacoma.
 Formed out of Thurston County on December 22, 1852, by the legislature of Oregon Territory, it was
 named for U.S. President Franklin Pierce. Pierce County is in the Seattle metropolitan area (formally the
 Seattle-Tacoma-Bellevue, WA metropolitan statistical area).

 Pierce County is home to Mount Rainier, the tallest mountain and a volcano in the Cascade Range. Its
 most recent recorded eruption was between 1820 and 1854. There is no imminent risk of eruption, but
 geologists expect that the volcano will erupt again. If this should happen, parts of Pierce County and the
 Puyallup Valley would be at risk from lahars, lava, or pyroclastic flows. The Mount Rainier Volcano Lahar
 Warning System was established in 1998 to assist in the evacuation of the Puyallup River valley in case of
 eruption.