Pierce County, Washington

Pierce County
Old City Hall in Tacoma.
Flag of Pierce County
Official seal of Pierce County
Map of Washington highlighting Pierce County
Location within the U.S. state of Washington
Map of the United States highlighting Washington
Washington's location within the U.S.
Coordinates: 47°03′N 122°07′W / 47.05°N 122.11°W / 47.05; -122.11
Country United States
State Washington
FoundedDecember 22, 1852
Named forFranklin Pierce
SeatTacoma
Largest cityTacoma
Area
 • Total1,806 sq mi (4,680 km2)
 • Land1,670 sq mi (4,300 km2)
 • Water137 sq mi (350 km2)  7.6%
Population
 (2020)
 • Total921,130
 • Estimate 
(2023)
928,696 Increase
 • Density510/sq mi (200/km2)
Time zoneUTC−8 (Pacific)
 • Summer (DST)UTC−7 (PDT)
Congressional districts6th, 8th, 10th
Websitepiercecountywa.gov
Mount Rainier from Ricksecker Point, 1932
Tacoma—seat of Pierce County
Mount Rainier hazard map

Pierce County is a county in the U.S. state of Washington. As of the 2020 census, the population was 921,130,[1] up from 795,225 in 2010, making it the second-most populous county in Washington, behind King County, and the 59th-most populous in the United States. The county seat and largest city is Tacoma.[2] Formed out of Thurston County on December 22, 1852, by the legislature of Oregon Territory,[3][4] 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 the volcano Mount Rainier, the tallest mountain 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.

  1. ^ "State & County QuickFacts". United States Census Bureau. Retrieved March 20, 2024.
  2. ^ "Find a County". National Association of Counties. Retrieved June 7, 2011.
  3. ^ Reinartz, Kay. "History of King County Government 1853–2002" (PDF). Archived from the original (PDF) on December 1, 2007. Retrieved December 29, 2007.