Washington Counties: The Complete Guide to All 39 Counties

I’ve lived in Washington state since 2018, and in that time I’ve visited 24 of the state’s 39 counties. King County is home — that’s where Seattle sits. But driving east on I-90 into Kittitas County, or south on I-5 through Pierce and Lewis Counties, or north through Skagit and Whatcom Counties toward the Canadian border, you start to see how much this state changes within its own borders. Washington has rain-soaked coastal counties, high-desert agricultural counties, mountain counties with more elk than people, and urban counties with populations larger than some states.

Washington state has 39 counties, ranging from King County (population 2.3+ million, home to Seattle) to Garfield County (population ~2,200, the least populated county in the state). The counties span roughly 71,362 square miles and cover Western Washington’s coastal and Puget Sound regions, Central Washington’s Cascade Range and agricultural valleys, and Eastern Washington’s high desert and wheat country.

This guide lists all 39 Washington counties with population, county seats, regions, and what each area is known for — from a local’s perspective.

How Many Counties Are in Washington State?

Washington has 39 counties. The state created its counties from the original Washington Territory, which was carved from the Oregon Territory in 1853.

Washington’s county system dates to the Provisional Government of Oregon and the Oregon Country era. When the U.S. government established the Washington Territory in 1853, the territory inherited county divisions from Oregon. Over the following decades, the Washington Supreme Court and territorial legislature subdivided, merged, and reorganized counties until the current 39 were set.

The 39 counties range from massive (Okanogan County covers 5,315 square miles — larger than Connecticut) to compact (San Juan County is 175 square miles spread across islands). The United States government conducts a U.S. Census every 10 years, and Washington’s Office of Financial Management releases annual population estimates for each county.

Washington’s counties operate under 2 structures: charter counties (which have adopted a home-rule charter with a county executive) and non-charter counties (governed by elected commissioners — typically 3). King, Pierce, Snohomish, Whatcom, Clark, and San Juan Counties are charter counties. The remaining 33 are non-charter counties governed by boards of commissioners. Each county has a county seat, a prosecuting attorney, and responsibility for unincorporated areas, roads and transportation, zoning and permitting, and other local services.

All 39 Washington Counties by Population

The 5 most populous Washington counties — King, Pierce, Snohomish, Spokane, and Clark — hold over 75% of the state’s population. The 20 smallest counties combined hold less than 5%.

Here are all 39 counties ranked by approximate population (based on the most recent estimates):

Rank	County	County Seat	Approx. Population	Region
1	King County	Seattle	2,370,000+	Puget Sound
2	Pierce County	Tacoma	950,000+	Puget Sound
3	Snohomish County	Everett	880,000+	Puget Sound
4	Spokane County	Spokane	560,000+	Eastern WA
5	Clark County	Vancouver	537,000+	SW Washington
6	Thurston County	Olympia	300,000+	Puget Sound
7	Kitsap County	Port Orchard	280,000+	Puget Sound
8	Yakima County	Yakima	260,000+	Central WA
9	Whatcom County	Bellingham	235,000+	NW Washington
10	Benton County	Prosser	215,000+	Central WA
11	Skagit County	Mount Vernon	135,000+	NW Washington
12	Grant County	Ephrata	110,000+	Central WA
13	Cowlitz County	Kelso	110,000+	SW Washington
14	Franklin County	Pasco	100,000+	Central WA
15	Island County	Coupeville	88,000+	Puget Sound
16	Lewis County	Chehalis	85,000+	SW Washington
17	Chelan County	Wenatchee	83,000+	Central WA
18	Grays Harbor County	Montesano	77,000+	Coast
19	Mason County	Shelton	70,000+	Puget Sound
20	Douglas County	Waterville	45,000+	Central WA
21	Walla Walla County	Walla Walla	64,000+	Eastern WA
22	Kittitas County	Ellensburg	49,000+	Central WA
23	Clallam County	Port Angeles	78,000+	Olympic Peninsula
24	Okanogan County	Okanogan	44,000+	NE Washington
25	Jefferson County	Port Townsend	33,000+	Olympic Peninsula
26	Stevens County	Colville	47,000+	NE Washington
27	Whitman County	Colfax	51,000+	Eastern WA
28	Pacific County	South Bend	24,000+	Coast
29	Klickitat County	Goldendale	23,000+	Central WA
30	San Juan County	Friday Harbor	18,000+	Islands
31	Adams County	Ritzville	21,000+	Eastern WA
32	Skamania County	Stevenson	12,500+	SW Washington
33	Pend Oreille County	Newport	14,000+	NE Washington
34	Lincoln County	Davenport	11,000+	Eastern WA
35	Asotin County	Asotin	23,000+	Eastern WA
36	Ferry County	Republic	7,500+	NE Washington
37	Wahkiakum County	Cathlamet	4,500+	SW Washington
38	Columbia County	Dayton	4,000+	Eastern WA
39	Garfield County	Pomeroy	2,200+	Eastern WA

Population figures are approximate and based on the most recent U.S. Census and state estimates. Rankings and exact figures shift annually.

Washington Counties by Region

Washington’s 39 counties fall into 5 general regions: Puget Sound (Western Washington’s urban core), Northwest Washington, Southwest Washington, Central Washington, and Eastern Washington.

Puget Sound / Major Metro Counties

The major counties on Puget Sound — King, Pierce, Snohomish, Kitsap, Thurston, Island, and Mason — hold the bulk of Washington’s population. King County alone contains Seattle, Bellevue, Redmond, Kirkland, and Renton. Pierce County holds Tacoma and Joint Base Lewis-McChord. Snohomish County includes Everett and the Boeing factory. Thurston County is home to Olympia, the state capital.

This is where most visitors to Seattle spend their time, and the region I know best after 8 years of living here. The population density in King County exceeds 1,000 people per square mile. Cross the Cascade Range heading east, and density drops to single digits in some counties.

Northwest Washington

Whatcom County (Bellingham) and Skagit County (Mount Vernon) sit north of the Puget Sound metro area along I-5 toward the Canadian border. Whatcom County is a charter county with a population of 235,000+ and a college-town character. Skagit County is known for the Skagit Valley tulip fields in spring. San Juan County — the San Juan Islands — is accessible only by ferry or small plane and has the smallest land area of any Washington county.

Southwest Washington

Clark County (Vancouver) sits across the Columbia River from Portland, Oregon, and has grown rapidly — over 537,000 residents. Cowlitz County (Kelso/Longview) is the gateway to Mount St. Helens. Lewis County (Centralia/Chehalis) sits on I-5 halfway between Seattle and Portland. Pacific County and Wahkiakum County are among the least populated, occupying the southern Washington coast and lower Columbia River.

Central Washington

Central Washington spans the Cascade Range foothills and the agricultural valleys on the eastern slope. Yakima County is the state’s primary agricultural producer — apples, hops, wine grapes. Chelan County includes Wenatchee and Leavenworth. Kittitas County holds Ellensburg and Snoqualmie Pass. Benton and Franklin Counties form the Tri-Cities area (Richland, Kennewick, Pasco) in the state’s south-central desert. Grant County includes the Grand Coulee Dam. Douglas and Klickitat Counties are sparsely populated with agriculture and wind farms.

Eastern Washington

Eastern Washington is a different state. Spokane County is the urban anchor with 560,000+ residents and the city of Spokane — the largest city between Seattle and Minneapolis. Whitman County holds Pullman and Washington State University. Walla Walla County is known for wine and onions. The northeastern counties — Stevens, Ferry, Pend Oreille, and Lincoln — are among the most remote and least populated in Washington, with forests, small towns, and a character closer to rural Idaho or Montana than to Seattle.

The southeastern counties — Asotin, Columbia, and Garfield — form the state’s least-populated corner. Garfield County, with roughly 2,200 residents, is the smallest county in Washington by population. Columbia County has about 4,000. These are wheat-farming counties with vast open landscapes and a pace of life that has nothing in common with King County’s tech corridors.

My honest take: If you only know Washington from visiting Seattle, you’ve seen about 5% of the state. Eastern Washington’s high desert looks like a different country. The Olympic Peninsula’s rainforests feel prehistoric. The San Juan Islands move at island time. The diversity between these 39 counties — geographically, culturally, economically — is what makes Washington one of the most interesting states in the country. I’ve driven through counties where the only business for 30 miles was a gas station, and I’ve driven through King County where you can’t go 30 feet without passing a tech office.

Washington Counties by Area (Largest to Smallest)

The largest Washington county by land area is Okanogan County at 5,315 square miles. The smallest is San Juan County at 175 square miles.

The 5 largest counties by area:

• Okanogan County: 5,315 sq mi — northeast Washington, bordering Canada
• Yakima County: 4,296 sq mi — central agricultural valley
• Chelan County: 2,920 sq mi — Cascade mountains and Wenatchee
• Grant County: 2,680 sq mi — central desert and Grand Coulee
• Klickitat County: 1,871 sq mi — Columbia River Gorge south side

The smallest counties by area are San Juan (175 sq mi), Island (208 sq mi), and Wahkiakum (264 sq mi).

FAQs

Q. How many counties does Washington state have?

39 counties. Washington has had 39 counties since Pend Oreille County was created in 1911.

Q. What is the largest county in Washington by population?

King County, with approximately 2.3 million residents. King County contains Seattle and most of the Puget Sound metro area.

Q. What is the smallest county in Washington by population?

Garfield County, with approximately 2,200 residents. Garfield County is in far southeast Washington.

Q. What is the largest county in Washington by area?

Okanogan County at 5,315 square miles. Okanogan County in northeast Washington is larger than the states of Connecticut and Rhode Island combined.

Q. How many charter counties does Washington have?

6 charter counties: King, Pierce, Snohomish, Whatcom, Clark, and San Juan. Charter counties operate under a home-rule charter with a county executive. The other 33 counties are governed by boards of elected commissioners.

Q. Which Washington counties allow RV living?

Rules vary by county. Several rural Washington counties — including Stevens, Ferry, Okanogan, and Lewis — have more permissive zoning for RV and mobile home living on private land. King, Pierce, and Snohomish Counties have stricter regulations. Check the specific county’s zoning and permitting office for current rules.

Final Thoughts

I moved to King County in 2018 and started exploring Seattle from day one. But the more I’ve driven around Washington — through the parks, over the mountains, across the ferry routes, and down the I-5 corridor — the more I’ve realized that understanding Washington means understanding its counties. Each one has its own geography, economy, and character.

King County has 2.3 million people and the headquarters of Amazon, Microsoft, and Starbucks. Garfield County has 2,200 people and wheat fields. They’re both Washington. And driving between them — watching the landscape shift from Puget Sound fog to Cascade peaks to high-desert grassland to rolling Palouse hills — is one of the best things about living here.

If you’re planning a trip to Seattle and want to understand the state beyond the city limits, this list is your starting point. Pick a county. Look at a map. Drive there. Washington has 39 of them, and each one gives you a different version of the Pacific Northwest.