
Lyon County
- State:
- Iowa
- County Seat:
- Rock Rapids
Lyon County's estimated 2025 population is 12,618 with a growth rate of 1.18% in the past year according to the most recent United States census data. Lyon County is the 59th largest county in Iowa. The 2010 population was 11,569 and has seen a growth of 9.07% since that time.