King County experienced a significant outflow of income as residents relocated to other counties and states, according to an analysis of 2022 and 2023 IRS tax return data by the Puget Sound Business Journal.
Between 2022 and 2023, King County recorded a net loss of $1.77 billion in adjusted gross income. The largest number of residents who left the county moved to nearby Snohomish and Pierce counties, with 17,266 and 16,244 people relocating there, respectively.
Among out-of-state destinations, Maricopa County, Arizona, attracted the largest share of former King County residents. About 2,460 people moved there, representing a net loss of approximately $150 million in adjusted gross income for King County. Other popular destinations include Los Angeles County, California, and counties in Texas, Nevada, Oregon, and Idaho.
The migration reflects broader national trends that accelerated during the pandemic. Remote work reduced the need for some workers to live near major employment centers, while housing costs and state tax policies have influenced relocation decisions.
At the same time, King County continued to experience modest overall population growth after a decline in 2021. The data also shows movement in the opposite direction, with King County gaining residents and income from several California counties, including Santa Clara, Los Angeles and Alameda.
Researchers cited housing affordability, economic conditions, and tax policies as factors influencing migration. They also noted potential fiscal impacts for communities that lose higher-income residents, including reduced local tax revenue and consumer spending.
The broader trend suggests that population and wealth are becoming more dispersed across metropolitan areas, with suburban and lower-density communities continuing to attract residents and economic activity.
