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Population of Counties in Washington (2024)

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2024 Population
Growth Since 2020
Area (mi²)
Density (/mi²)
King County2,277,4490.14%8171,076King County location
Pierce County930,9130.79%644558Pierce County location
Snohomish County849,0702.31%806407Snohomish County location
Spokane County553,1702.22%681314Spokane County location
Clark County525,5634%242837Clark County location
Thurston County299,3671.14%279414Thurston County location
Kitsap County277,5030.61%152703Kitsap County location
Yakima County256,267-0.18%1.7K60Yakima County location
Whatcom County233,2402.55%814111Whatcom County location
Benton County217,6094.91%656128Benton County location
Skagit County131,5121.24%66876Skagit County location
Cowlitz County113,6642.39%440100Cowlitz County location
Grant County103,7764.36%1K39Grant County location
Franklin County99,4862.4%47980Franklin County location
Lewis County86,9515.33%92836Lewis County location
Island County85,852-1.32%80413Island County location
Chelan County79,9560.91%1.1K27Chelan County location
Clallam County77,5480.23%67145Clallam County location
Grays Harbor County77,5392.22%73441Grays Harbor County location
Mason County68,6073.9%37171Mason County location
Walla Walla County61,283-2.14%49048Walla Walla County location
Stevens County49,3916.01%95620Stevens County location
Whitman County48,4451.33%83322Whitman County location
Kittitas County45,8942.9%88720Kittitas County location
Douglas County45,3735.45%70225Douglas County location
Okanogan County43,9644.33%2K8Okanogan County location
Jefferson County33,8582.41%69619Jefferson County location
Pacific County24,3053.45%36026Pacific County location
Klickitat County23,8754.65%72313Klickitat County location
Asotin County22,5621.07%24535Asotin County location
Adams County20,7420.66%74311Adams County location
San Juan County18,4603.56%67106San Juan County location
Pend Oreille County14,5848.01%54010Pend Oreille County location
Skamania County12,8256.51%6408Skamania County location
Lincoln County11,8638.56%8925Lincoln County location
Ferry County7,5264.56%8503Ferry County location
Wahkiakum County4,8428.86%10218Wahkiakum County location
Columbia County4,0803.32%3355Columbia County location
Garfield County2,3693.27%2743Garfield County location
showing: 39 rows

There are 39 counties in Washington. As of 2019, Washington's most populous county is King County, home to Seattle, with a population of 2,188,649. This represents a population growth of 12.97% since the 2010 census. King County is followed by Piece County (876,764), Snohomish County (801,633), and Spokane County (506,152) in terms of population. These are the only counties with a population of more than 500,000. All four counties have posted significant growth since the census ranging from 7% to almost 13%.

Washington Counties with Fewest Residents

The least populous Washington county is Garfield County with a population of 2,210. This represents a population decline of 2.26% since the last census. Other sparsely populated counties in Washington include Columbia County (4,047), Wahkiakum County (4,264), and Ferry County (7,594). These are the only counties in Washington with a population under 10,000. Three of these counties reported a population decline since 2010. Wahkiakum County had population growth of 7.05% since the last census.

Washington Counties with Rapid Growth

Franklin County has boasted the highest population growth rate in Washington since the last census, growing 16.48% to 92,125. Four other cities have experienced population growth above 12%: King County (12.97%), Kittitas County (12.74%), Benton County (12.30%), and Snohomish County (12.05%). The county with the largest negative growth is Garfield County at -2.26%.

Lists of Counties in all States

  1. Washington Data & Research
  2. US Census State Population Estimates - Most recent state estimates from the Census Bureau's Population Estimates Program
  3. US Census County Population Estimates - Most recent county estimates from the Census Bureau's Population Estimates Program
  4. American Community Survey (2009 - 2013)
  5. Census QuickFacts
  6. Historical Populations of States and Counties (1790 - 1990)