International immigration became the main source of population growth in King County after Seattle’s technology boom in the 2010s. From 2010 to 2020, it added about 159,000 residents to the county, while domestic migration added fewer than 44,000. From 2020 to 2025, approximately 132,000 more people moved in from abroad, while the number of people relocating from other parts of the United States declined by 95,000.
Growth is concentrated mainly in two areas: the suburban technology corridor on the Eastside and densely populated central Seattle. The most significant increase occurred in Issaquah Highlands, where the number of foreign-born residents rose from fewer than 500 in 2015 to nearly 3,600 in 2024. More than 70% were born in Asia, and immigrants make up over 40% of the neighborhood’s population. It is an affluent area, with a median household income of about $170,000; more than one-fifth of full-time workers are employed in the technology industry.
Next are downtown Redmond and the Overlake neighborhood on the border between Bellevue and Redmond, home to major Microsoft facilities. They gained approximately 2,500 and 2,300 immigrants, respectively. Two more top areas are in central Seattle — Belltown and Denny Triangle, near Amazon’s campus. In all five neighborhoods, people from Asian countries make up a significant share of new residents, and the proportion of technology-sector workers is particularly high. These figures reflect conditions through the end of 2024, so the potential impact of the Donald Trump administration’s tougher immigration policies cannot yet be assessed. The figures are based on five-year averages from the U.S. Census Bureau.
Based on: King County’s immigration boom is concentrated in these neighborhoods