King County attracts new residents from around the country and around the world — that's nothing new. But as the rate of new arrivals has picked up, the share of county residents who were born in-state just hit its lowest point in nearly 100 years.
In 2024, only about 38% of King County’s 2.34 million residents were born in the state — roughly 880,000 people — according to the latest census data.
That's slightly lower than the 39% who were born in Washington in the 1940 census, but still higher than the figure from 1930, which was 33%.
The state of Washington was only founded in 1889, so it makes sense that in the early years, relatively few were born in the state. In the 1900 census, around 17% of King County's population was born in Washington. That figure kept rising until it nearly reached 50% during the period from 1960 to 1980. Then it began to fall.
From 2010 to 2014, the number of Washington-born county residents rose by around 9%. But the number of people born elsewhere grew much faster, at around 29%.
Where people not born in Washington are coming from remains diverse: the top 10 places of origin include five states and five countries.
Let's look at the states first.
Californians have been relocating to the Seattle area in large numbers for decades, and it's no surprise that California was easily the No. 1 source of transplants. In 2024, King County residents born in the Golden State totaled about 184,000, a 16% increase since 2010.
Oregon remained at No. 2 among the states, the place of birth for about 46,000 King County residents. That's a modest 8% increase since 2010, and Oregon is likely to fall from second place at some point because the next states, New York and Texas, have increased at a significantly faster rate.
The number of transplants from No. 3 New York grew by 29% since 2010, to about 43,000. And fourth-ranked Texas, birthplace of nearly 38,000 King County residents, grew at an even faster rate, up by 32%.
Illinois rounded out the top five states. About 35,000 King County residents were born in the Land of Lincoln. But Illinois was the only state in the top 5 to show a decline, down around 6% since 2010.
Florida didn't quite make the Top 5, ranking No. 9 with about 21,000 King County residents born there, but it's worth mentioning because of the sharp growth rate. The number of county residents born in the Sunshine State nearly doubled since 2010, up by 90%.
International immigration has been a bigger driver of growth than domestic migration in King County in recent years. From 2010 to 2014, the number of county residents born in another country increased from around 426,000 to 684,000, a growth rate of about 60%. The number born in another state grew by about 10%.
India led foreign birthplaces, with nearly 95,000 King County residents in 2024, about three times the 2010 total of 32,000. After California, India was the top place of birth, well ahead of Oregon.
China followed closely, with 83,000 people, slightly more than three times the 2010 total of 27,000.
Together, India and China account for a large share of the recent surge in foreign-born residents. Of course, the Seattle-area tech boom of the 2010s, led by Amazon, drew thousands of workers from these two countries to King County.
Mexico was the third-largest foreign birthplace, with about 56,000 people, but that number had barely changed since 2010, when Mexico ranked No. 1 among foreign countries as a place of birth for King County residents.
About 43,000 people in King County were born in Vietnam, ranking fourth; the Philippines ranked fifth, with about 33,000. Both have grown steadily, at 18% and 13%, respectively, since 2010.
The largest growth rate among countries in this period was Afghanistan, which ranked 10th and was the birthplace of about 14,000 King County residents in 2024. In 2010, only around 500 people in the county were born there. Roughly 200,000 Afghan refugees have arrived in the United States since the withdrawal of U.S. forces in August 2021.
© 2026 The Seattle Times. Visit www.seattletimes.com. Distributed by Tribune Content Agency, LLC.
