King County’s population grew last year, but not by much, according to data released Thursday by the U.S. Census Bureau. Even so, it was enough for King to move up the rankings of the largest U.S. counties for the first time in more than a decade.
The data shows from July 1, 2022, to July 1, 2023, King County only gained about 6,100 people, for a growth rate of 0.3%. That’s around half the rate of the previous one-year period.
Last year’s growth looks especially anemic compared with the pre-pandemic period. For example, from 2018 to 2019, King County gained more than 24,000 residents, growing by 1.1%.
While 2023 wasn’t a banner year for growth, it still propelled King County from the 13th to the 12th spot among the nation’s most populous counties. In what sounds almost like a chess move, King overtook Queens.
Queens County, New York, which is also one of New York City’s five boroughs, had previously ranked as the 12th largest U.S. county. But in the new data, its population fell by more than 26,000. With that big decline, King County and Queens County switched places. King’s population hit 2.27 million in 2023, while Queens’ fell to 2.25 million.
This marks the first change in King County’s population ranking since 2011. That year, King jumped from 14th to 13th among U.S. counties by surpassing Clark County, Nevada, where Las Vegas is located. Since then, Clark County grew at a faster rate than King, and is now the 11th most populous county.
Among the 50 largest U.S. counties, King County’s 0.3% growth rate ranked in the middle of the pack, at 22nd. Collin County, Texas, which is in the Dallas-Fort Worth metro area, had the fastest growth rate, at 3.1%. All of the 10 fastest-growing large counties were in three states: Texas, Florida and North Carolina.
Harris County, Texas, where Houston is located, had the biggest numeric population gain of any county, at around 54,000.
Nineteen of the 50 largest counties lost people last year. The three biggest declines were all in New York City: Bronx County fell by 1.8%, followed by Queens at 1.2% and Kings (Brooklyn) at 1.1%.
Los Angeles County had the largest numeric decline in population, down by about 56,000.
The data breaks out the components of population change, including “natural” change (the number of births minus the number of deaths) and net migration, both domestic and international.
Last year, King County grew from a natural increase and international migration, but lost most of those gains to domestic migration — in other words, people moving to other U.S. counties.
There were nearly 23,000 births and 15,000 deaths among county residents — that pencils out to a natural increase of almost 8,000.
The county gained an additional 19,000 residents from people moving here from other countries.
But most of these gains were wiped out by a net loss of more than 20,000 from domestic migration. After subtracting the loss from these movers to other U.S. counties, King County only had a net gain of 6,100 residents.
King County’s growth in 2023 slowed from one year earlier, when the county grew by about 14,000 residents. In 2022, the gains from international migration exceeded the loss from domestic movers, which was not the case last year.
The Census Bureau only provides a net figure for domestic migration. While it showed King County lost population to other counties, it doesn’t tell us how many people moved into King County versus how many left.
Another thing the data doesn’t tell us, unfortunately, is where all the folks who left King County went. But typically, Pierce and Snohomish counties are the two biggest gainers from King.
Both Snohomish and Pierce counties recorded modest growth last year. Snohomish gained about 4,300 residents, for a growth rate of 0.5%, while Pierce only added about 2,200 people, for a 0.2% growth rate.
Two of Washington’s sparsely populated rural counties — Wahkiakum and Pend Oreille — grew by 1.6% each, the fastest rate of growth in the state last year. Eight of Washington’s 39 counties lost population. San Juan County saw the sharpest decline, with a population loss of 0.6%.
Washington’s population hit 7.81 million last year. The state gained about 28,000 residents for a growth rate of 0.4%.
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