
Jefferson County
- State:
- Washington
- County Seat:
- Port Townsend
Jefferson County's estimated 2025 population is 34,002 with a growth rate of 0.43% in the past year according to the most recent United States census data. Jefferson County is the 27th largest county in Washington. The 2010 population was 29,899 and has seen a growth of 13.72% since that time.