[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 home to the volcano Mount Rainier, the tallest mountain in the Cascade Range.

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.

[5] The highest natural point in Washington, Mount Rainier, at 14,410 feet (4,390 m), is located in Pierce County.

The majority of Puyallup villages were situated in proximity to the area that would eventually develop into Tacoma, while Nisqually settlements were primarily located in what is now southern Pierce County.

[13] In 1792 British Captain George Vancouver and his party of explorers came via ship to the shores of the region, and named a number of sites in what would become Pierce County, i.e. Mt.

[citation needed] In 1832 Fort Nisqually was sited by the British Hudson's Bay Company's chief trader, Archibald McDonald.

In cooperation with the local indigenous people, a storehouse for blankets, seeds, and potatoes was built at the mouth of Sequalitchew Creek.

In 1839 the Nisqually Methodist Episcopal Mission was established,[14] bringing the first U.S. citizens to settle in the Puget Sound region, near the Sequalitchew Creek canyon.

In 1841 the United States Exploring Expedition set up an observatory on the bluff near the creek to survey, map and chart the waters of Puget Sound.

Business became mainly agricultural, and the fort was relocated on a flat-plains area near the banks of Sequalitchew Creek for cattle.

In 1846 the Oregon Treaty established the 49th Parallel as the boundary between British Canada and the United States, which left what was to become Pierce County on U.S. territory.

In 1850, Captain Lafayette Balch sited his land claim next to the fort and founded Port Steilacoom.

In 1854 the Treaty of Medicine Creek was enacted between the United States and the local tribes occupying the lands of the Salish Sea.

The tribes listed on the Treaty of Medicine Creek are Nisqually, Puyallup, Steilacoom, Squawskin (Squaxin Island), S'Homamish, Stehchass, T'Peeksin, Squi-aitl, and Sa-heh-wamish.

The treaty was signed on December 26, 1854, by Isaac I. Stevens, governor and superintendent of Indian Affairs of Washington territory at the time.

[citation needed] When the natives refused to leave, Isaac Stevens would eventually call martial law and - after the beginning of the Puget Sound War in 1855 - initiate a search for Chief Leschi in order to arrest him.

[13] On December 10, 2004, a historical court convened in Pierce County ruled "as a legal combatant of the Indian War Leschi should not have been held accountable under law for the death of an enemy soldier," thereby exonerating him of any wrongdoing.

[17] The Assessor-Treasurer Marty Campbell,[18] auditor Linda Farmer, Prosecuting Attorney Mary Robnett,[19] and Sheriff Keith Swank.

[31] There are currently 20 branches, including: The Pierce County Library System currently employs 394 people, and serves 579,970 citizens throughout 1,773 square miles.

Established in 1944, the library system serves all of unincorporated Pierce County, as well as annexed cities and towns of: Bonney Lake, Buckley, DuPont, Eatonville, Edgewood, Fife, Gig Harbor, Lakewood, Milton, Orting, South Prairie, Steilacoom, Sumner, University Place and Wilkeson.

An economic impact study showed that more the 28,000 jobs in Pierce County are related to the Port activities.

On December 18, 2017, an Amtrak train derailed in the county, at an overpass over southbound Interstate 5, hitting several vehicles.

[44] Pierce County was noted for gangs, drugs, and criminal activity starting in the mid to late 1980s.

Increased police patrols and community watch programs led to reduced crime in the mid to late 2000s.

As of 2006, 38% of the methamphetamine labs (138 sites) cleaned up by the Washington State Department of Ecology were in Pierce County.