48°06'39"N 123°53'23"W
Population: 77,616
County Seat: Port Angeles
Largest City: Port Angeles
Founded: April 26, 1854
Square Miles: 2,671
Time Zone: Pacific
Named For: Klallum Tribe
Website: www.clallamcountywa.gov
47°50'39"N 123°35'W
Population: 32,977
County Seat: Port Townsend
Largest City: Port Townsend
Founded: December 22, 1852
Square Miles: 2,183
Time Zone: Pacific
Named For: Thomas Jefferson
Website: www.co.jefferson.wa.us
xxx°xxx'xxx"N xxx°xxx'W
Population: 75,636
County Seat: Montesano
Largest City: Aberdeen
Founded: April 14, 1854
Square Miles: 2,224
Time Zone: Pacific
Named For: Grays Harbor
Website: www.co.grays-harbor.wa.us
46°34'39"N 123°47'W
Population: 24,200
County Seat: South Bend
Largest City: Raymond
Founded: February 4, 1851
Square Miles: 1,223
Time Zone: Pacific
Named For: Pacific Ocean
Website: www.co.pacific.wa.us
48°50'34"N 121°50'11"W
Population: 226,847
County Seat: Bellingham
Largest City: Bellingham
Founded: March 9, 1854
Square Miles: 2,503
Time Zone: Pacific
Named For: Chief Whatcom
Website: whatcomcounty.us
46°17'N 123°26'W
Population: 4,422
County Seat: Cathlamet
Largest City: Puget Island
Founded: April 24, 1854
Square Miles: 287
Time Zone: Pacific
Named For: Chief Wahkiakum
Website: www.co.wahkiakum.wa.us
48°29'N 121°47'W
Population: 129,523
County Seat: Mount Vernon
Largest City: Mount Vernon
Founded: November 28, 1883
Square Miles: 1,920
Time Zone: Pacific
Named For: Skagit tribes
Website: skagitcounty.net
48°02'N 121°43'W
Population: 827,957
County Seat: Everett
Largest City: Everett
Founded: January 14, 1861
Square Miles: 2,196
Time Zone: Pacific
Named For: Snohomish People
Website: snohomishcountywa.gov
47°28'N 121°50'W
Population: 2,269,675
County Seat: Seattle
Largest City: Seattle
Founded: December 22, 1852
Square Miles: 2,307
Time Zone: Pacific
Named For: William R. King
Website: kingcounty.gov
47°03'N 122°07'W
Population: 921,130
County Seat: Tacoma
Largest City: Tacoma
Founded: December 22, 1852
Square Miles: 1,806
Time Zone: Pacific
Named For: Franklin Pierce
Website: piercecountywa.gov
47°21'N 123°11'W
Population: 65,726
County Seat: Shelton
Largest City: Shelton
Founded: March 13, 1854
Square Miles: 1,051
Time Zone: Pacific
Named For: Charles H. Mason
Website: masoncountywa.gov
46°56'N 122°50'W
Population: 294,793
County Seat: Olympia
Largest City: Lacey
Founded: January 12, 1852
Square Miles: 774
Time Zone: Pacific
Named For: Samuel Thurston
Website: thurstoncountywa.gov
46°35'N 122°24'W
Population: 82,149
County Seat: Chehalis
Largest City: Chehalis
Founded: December 19, 1845
Square Miles: 2,436
Time Zone: Pacific
Named For: Meriwether Lewis
Website: lewiscountywa.gov
47°64'N 122°65'W
Population: 275,611
County Seat: Port Orchard
Largest City: Bremerton
Founded: January 16, 1857
Square Miles: 566
Time Zone: Pacific
Named For: Chief Kitsap
Website: kitsap.gov
48°34'N 122°58'W
Population: 18,566
County Seat: Friday Harbor
Largest City: Friday Harbor
Founded: October 31, 1873
Square Miles: 621
Time Zone: Pacific
Named For: San Juan Islands
Website: www.sanjuanco.com
48°32'54"N 119°44'32"W
Population: 42,104
County Seat: Okanogan
Largest City: Omak
Founded: February 2, 1888
Square Miles: 5,312.7
Time Zone: Pacific
Named For: Fort Okanogan
Website: okanogancounty.org
47°51'40"N 120°37'09"W
Population: 79,074
County Seat: Wenatchee
Largest City: Wenatchee
Founded: March 13, 1899
Square Miles: 2,994
Time Zone: Pacific
Named For: Chelan Indian Word meaning "Deep Water"
Website: co.chelan.wa.us
47°44'N 119°41'W
Population: 42,938
County Seat: Waterville
Largest City: East Wenatchee
Founded: November 28, 1883
Square Miles: 1,849
Time Zone: Pacific
Named For: Stephen A. Douglas
Website: douglascountywa.net
47°07'28"N 120°40'36"W
Population: 44,337
County Seat: Ellensburg
Largest City: Ellensburg
Founded: November 24, 1883
Square Miles: 2,333
Time Zone: Pacific
Named For: Kittitas Tribe
Website: co.kittitas.wa.us
46°28'N 120°44'W
Population: 256,728
County Seat: Yakima
Largest City: Yakima
Founded: January 21, 1865
Square Miles: 4,311
Time Zone: Pacific
Named For: Yakama Nation
Website: www.yakimacounty.us
46°11'48"N 122°40'42"W
Population: 110,730
County Seat: Kelso
Largest City: Longview
Founded: April 21, 1854
Square Miles: 1,166
Time Zone: Pacific
Named For: Cowlitz Tribe
Website: co.cowlitz.wa.us
45°46'N 122°29'W
Population: 503,311
County Seat: Vancouver
Largest City: Vancouver
Founded: August 20, 1845
Square Miles: 656
Time Zone: Pacific
Named For: William Clark
Website: clark.wa.gov
46°02'N 121°55'W
Population: 12,036
County Seat: Stevenson
Largest City: Carson
Founded: March 9, 1854
Square Miles: 1,683
Time Zone: Pacific
Named For: Chinook Word Meaning “Swift Waters”
Website: skamaniacounty.org
45°52'N 120°47'W
Population: 22,735
County Seat: Goldendale
Largest City: Goldendale
Founded: December 20, 1859
Square Miles: 1,904
Time Zone: Pacific
Named For: Klickitat Tribe
Website: www.klickitatcounty.org
47°12'49"N 119°28'04"W
Population: 99,123
County Seat: Ephrata
Largest City: Moses Lake
Founded: February 24, 1909
Square Miles: 2,791
Time Zone: Pacific
Named For: Ulysses S. Grant
Website: grantcountywa.gov
48°28'N 118°31'W
Population: 7,178
County Seat: Republic
Largest City: Republic
Founded: February 21, 1899
Square Miles: 2,257
Time Zone: Pacific
Named For: Elisha P. Ferry
Website: www.ferry-county.com
48°32'38"N 13°56'W
Population: 13,401
County Seat: Newport
Largest City: Newport
Founded: March 1, 1911
Square Miles: 1,425
Time Zone: Pacific
Named For: Pend Oreille Tribe
Website: pendoreille.gov
48°24'N 117°51'W
Population: 46,445
County Seat: Colville
Largest City: Colville
Founded: January 20, 1863
Square Miles: 2,541
Time Zone: Pacific
Named For: Isaac Stevens
Website: stevenscountywa.gov
47°34'58"N 118°25'04"W
Population: 10,876
County Seat: Davenport
Largest City: Davenport
Founded: November 24, 1883
Square Miles: 2,339
Time Zone: Pacific
Named For: Abraham Lincoln
Website: co.lincoln.wa.us
47°37'N 117°24'W
Population: 539,339
County Seat: Spokane
Largest City: Spokane
Founded: January 29, 1858
Square Miles: 1,781
Time Zone: Pacific
Named For: Spokane Tribe
Website: www.spokanecounty.org
47°00'40"N 118°30'46"W
Population: 20,613
County Seat: Ritzville
Largest City: Othello
Founded: November 28, 1883
Square Miles: 1,929.802
Time Zone: Pacific
Named For: John Adams
Website: co.adams.wa.us
46°53'N 117°31'W
Population: 47,973
County Seat: Colfax
Largest City: Pullman
Founded: November 29, 1871
Square Miles: 2,178
Time Zone: Pacific
Named For: Marcus Whitman
Website: whitmancounty.org
46°15'N 119°30'W
Population: 206,873
County Seat: Prosser
Largest City: Kennewick
Founded: March 8, 1905
Square Miles: 1,760
Time Zone: Pacific
Named For: Thomas Hart Benton
Website: bentoncountywa.gov
46°32'N 118°54'W
Population: 96,749
County Seat: Pasco
Largest City: Pasco
Founded: November 28, 1883
Square Miles: 1,265
Time Zone: Pacific
Named For: Benjamin Franklin
Website: www.co.franklin.wa.us
46°14'N 118°29'W
Population: 62,584
County Seat: Walla Walla
Largest City: Walla Walla
Founded: April 25, 1854
Square Miles: xxx
Time Zone: Pacific
Named For: Walla Walla Tribe
Website: co.walla-walla.wa.us
46°18'N 117°55'W
Population: 3,952
County Seat: Dayton
Largest City: Dayton
Founded: November 11, 1875
Square Miles: 873
Time Zone: Pacific
Named For: Columbia River
Website: www.columbiaco.com
46°26'N 117°32'W
Population: 2,286
County Seat: Pomeroy
Largest City: Pomeroy
Founded: November 29, 1881
Square Miles: 718
Time Zone: Pacific
Named For: James A. Garfield
Website: www.co.garfield.wa.us
46°11'N 117°11'W
Population: 22,285
County Seat: Asotin
Largest City: Clarkston
Founded: October 27, 1883
Square Miles: 641
Time Zone: Pacific
Named For: Asotin Creek
Website: www.co.asotin.wa.us