
Washington County
- State:
- Tennessee
- County Seat:
- Jonesborough
Washington County's estimated 2025 population is 142,966 with a growth rate of 1.62% in the past year according to the most recent United States census data. Washington County is the 12th largest county in Tennessee. The 2010 population was 123,393 and has seen a growth of 15.86% since that time.