Thurston County is a county located in the U.S. state of Washington. As of the 2020 census, its population was 294,793. The county seat is Olympia, the state capital.

Thurston County was created out of Lewis County by the government of Oregon Territory on January 12, 1852. At that time, it covered all of the Puget Sound region and the Olympic Peninsula. On December 22 of the same year, Pierce, King, Island, and Jefferson counties were split off from Thurston County. It is named after Samuel R. Thurston, the Oregon Territory's first delegate to Congress. Today, the county includes the southernmost part of the South Puget Sound and areas south along the I-5 corridor.

Thurston County comprises the Olympia–Lacey–Tumwater, WA Metropolitan Statistical Area and is included in the Seattle–Tacoma, WA Combined Statistical Area.

History

The southern end of Puget Sound is the homeland of several indigenous Coast Salish groups, including the Nisqually, Squaxin, and Upper Chehalis. Archeological remains at Tumwater Falls date back to 2,500 to 3,000 years before present; the area around the falls included a settlement with several longhouses. The first European exhibition to the southern Puget Sound was conducted by Peter Puget and Joseph Whidbey on the British-led Vancouver Expedition in May 1792. The Hudson's Bay Company established a trading post at Fort Nisqually in 1833 on the east side of the Nisqually Delta while the Oregon Country was under joint administration by the British and American governments. Permanent European (and later American) settlement of modern-day Thurston County began with the arrival of a pioneer party led by Michael Simmons and Black pioneer George Bush in 1845. Several families settled near Tumwater Falls at a site they named "New Market", which became the first European settlement in Western Washington.

The area north of the Columbia River was originally under the jurisdiction of the Vancouver District (later renamed Clark County) until 1845, when Lewis County was created from the area west of the Cowlitz River. The entire region was ceded to the United States with the signing of the Oregon Treaty in 1846 and organized into Oregon Territory two years later. A petition by 54 residents of Olympia and surrounding communities was submitted to the Oregon Territorial Legislature in December 1851 to create a new county from Lewis County. The proposed name of Simmons County, named for Michael Simmons, was changed to Thurston County by the legislature at the suggestion of Asa Lovejoy to honor Samuel Thurston, the first delegate to the U.S. Congress from Oregon Territory. Thurston himself had never visited the area.

Thurston County was created on January 12, 1852, by the Oregon Territorial Legislature and Olympia was designated as its seat. It included the entire Olympic Peninsula and Puget Sound region up to the northern border with British North America and went as far east as the Cascade Mountains. On December 22, the northern areas of Thurston County were divided to form Island, Jefferson, King, and Pierce counties. A portion of the county south of the Chehalis River was ceded to Lewis County in February 1853, a month before Washington Territory was created with its capital in Olympia. Sawamish County (now Mason County) was created in March 1854 from the northwestern portions of Thurston County and Chehalis County (now Grays Harbor County) was established a month later from the remaining western half of Thurston County. Several exchanges of land between Thurston and neighboring counties were made during the 1860s and settled into the modern boundaries by 1873. An attempt to move the county seat from Olympia to Tumwater or West Olympia was defeated by voters in 1861.

Olympia was retained as capital of Washington after it was granted statehood in 1889; the city did not win a majority in the first referendum after Ellensburg and North Yakima, but defeated both in a second vote. Local residents built a branch line to connect with the Northern Pacific Railroad and approved a harbor-dredging operation to promote Olympia as a trade hub as the area fell behind Seattle and Tacoma in population growth.

The Old Capitol Building was completed in 1892 and was purchased by the state government in 1901 for use to replace a temporary wooden structure built in 1856. The modern Washington State Capitol commenced construction in 1923 and was completed in 1928 alongside a campus of government buildings and monuments. Thurston County remained predominantly dependent on the logging industry until the state government became the county's largest employment sector in the 1950s. Several state government agencies had attempted to move their offices to Seattle until a 1954 Washington Supreme Court ruling mandated that their headquarters remain in the Olympia area.

The first section of Interstate 5 built in Thurston County was the Olympia Freeway, which opened in December 1958 to bypass the city's downtown. Other sections opened over the following decade, extending access through Lacey and Tumwater, where it destroyed portions of the historic downtown; a proposal to build the freeway further away from Olympia was rejected to preserve rural areas. The completion of Interstate 5 enabled the growth of bedroom communities around Thurston County, which saw its population rapidly increase from the 1950s to 1970s. The first suburban shopping center in the county, the South Sound Center in Lacey, opened in October 1966; it was followed by Lacey's incorporation as a city. The Evergreen State College, a public liberal arts college in western Olympia, opened in 1972.

Thurston County, like many of the other counties in Western Washington, has a racially restrictive past. Racial segregation in Washington was different from the well-known accounts of Southern segregation during the Jim Crow era. While Southern states required racial segregation in public facilities by law, much of the racial segregation in Washington was accomplished through racial restrictive covenants which were legally binding agreements between private parties. These covenants were often included in property deeds between individual buyers and sellers, who agreed to never sell the property to specified racial or religious groups. In some cases, large groups of property owners would come together to implement racial restrictive covenants on entire subdivisions or neighborhoods, which are called petitions. In Thurston County specifically, many covenants excluded any Black, mixed race, Chinese, Japanese, or Indian individuals from purchasing, renting, leasing, or occupying specified properties. In rarer cases, Italians and Jewish individuals were also excluded from homeownership. The late 1930s to the early 1950s saw the largest number of racial restrictive covenants enacted. This history of segregation has had generational effects that are still felt today as people of color were systematically denied the ability to purchase homes and in turn were denied the ability to accrue generational wealth that comes with owning a home.

Geography According to the United States Census Bureau, the county has a total area of , of which is land and (6.7%) is water.

Adjacent counties Pierce County – northeast Lewis County – south Grays Harbor County – west Mason County – north/northwest

Major highways Interstate 5 U.S. 12 U.S. 101 SR 8 SR 507 SR 510

Geographic features Major watersheds: Black River, Budd/Deschutes, Chehalis River, Eld Inlet, Henderson Inlet, Nisqually River, Skookumchuck River, Totten Inlet and West Capitol Forest.

Alder Lake Bald Hill Lake Barnes Lake Bass Lake Bigelow Lake Black Lake Black River Budd Inlet Capitol Lake Capitol Peak Capitol State Forest Chambers Lake Chehalis River Clear Lake Deep Lake Deschutes River Elbow Lake Eld Inlet Fifteen Lake Gehrke Lake Grass Lake Henderson Inlet Hewitt Lake Hicks Lake Lake Lawrence Lake Lois Libby Creek Long Lake McIntosh Lake Mima Mounds Munn Lake Nisqually River Offut Lake Patterson Lake Puget Sound Reichel Lake Rocky Prairie Saint Clair Lake Scott Lake Simmons Lake Skookumchuck River Smith Lake Southwick Lake Springer Lake Summit Lake Susan Lake Totten Inlet Trails End Lake Trosper Lake Ward Lake

National protected areas Nisqually National Wildlife Refuge

Ecology and environment The habitat for the Golden Paintbrush (Castilleja levisecta) runs through the county. The plant was placed on the Endangered Species list in 1997 but due to conservation efforts the tall prairie flower was delisted in 2023.

Wildlife and land preserves in South Thurston County include the Black River Habitat Management Area, the Glacial Heritage Preserve, and the Scatter Creek Wildlife Area.

Economy

Employment

, Thurston County had 133,300 non-farm jobs and an unemployment rate of 3.5% (without adjustments for seasonal labor); there was a total of 4,983 unemployed individuals.

The mean hourly wage in the Olympia-Lacey-Tumwater metropolitan statistical area across all non-farm occupations was $35.18 in May 2024, which is above the national average of $32.66.

, Thurston County had 143,640 employed individuals; the county's top employers were:

Rank Employer Employees in 2023 Employees in 2014 2023 Share 2014 Share 1 State Government, including Education 28,700 23,896 19.98% 20.42% 2 Local Government, including Education 12,700 11,910 8.84% 10.18% 3 Providence Health & Services 2,600 1,600 1.81% 1.37% 4 Albertsons/Safeway 1,200 876 0.84% 0.75% 5 Walmart 1,100 1,023 0.77% 0.87% 6 Lucky Eagle Casino 1,000 600 0.70% 0.51% 7 Federal Government 900 862 0.63% 0.74% 8 Nisqually Red Wind Casino 700 600 0.49% 0.51% 9 South Sound YMCA 550 - 0.38% 0% 10 Continuum Global Solutions 500 - 0.35% 0% 10 Fred Meyer 500 - 0.35% 0% 10 Great Wolf Lodge 500 - 0.35% 0% 10 Northwest Cannabis Solutions 500 - 0.35% 0%

Tourism In 2024, the county was visited by 3.39million people, generating over $572 million in revenue. Over 4,000 jobs were supported by the tourism industry which produced more than $56 million in combined tax revenues at the local and county level.

Demographics

Thurston County has the sixth-largest population among Washington's counties and is among the fastest-growing in the state. From 2010 to 2020, the county's population became more ethnically diverse, with the number of residents who identify as Hispanic or Latino increasing by 63.2%. The county's largest city is Lacey, which has an estimated population of over 60,000 and surpassed Olympia's population in the early 2020s. The smallest incorporated place in Thurston County is the town of Bucoda, which has 620 residents. Over 145,000 people live in the unincorporated areas of the county, which are primarily concentrated between Olympia and Lacey.

The entire county is designated as part of the Olympia–Lacey–Tumwater Metropolitan Statistical Area (MSA), which only includes Thurston County. The MSA was among the fastest-growing metropolitan areas in the U.S. in the 2010s, with a year-to-year population increase of 2.24 percent. The county also had the highest population of middle class households among metropolitan areas in the U.S. according to a 2024 Pew Research study, which determined that 66 percent of households had adults with an annual income near double the national median household income. Thurston County is also part of the Seattle–Tacoma, WA Combined Statistical Area, which includes most of the Puget Sound region.

2020 census