Population growth shifts across Seattle-area cities as suburbs gain momentum

New data from the Washington State Office of Financial Management shows that the Seattle metropolitan area — consisting of King, Pierce and Snohomish counties — gained 26,000 residents between April 2025 and April 2026. At 0.6%, that represents the slowest population growth rate so far this decade. Gains have slowed in core cities, while smaller suburban cities in South King, Pierce and Snohomish counties are seeing accelerating growth.