
King William County
- State:
- Virginia
- County Seat:
- King William
King William County's estimated 2025 population is 20,032 with a growth rate of 2.57% in the past year according to the most recent United States census data. King William County is the 81st largest county in Virginia. The 2010 population was 15,999 and has seen a growth of 25.21% since that time.