Lyon County, Iowa

Lyon County
Location within the U.S. state of Iowa
Iowa's location within the U.S.
Coordinates: 43°23′00″N 96°13′00″W / 43.383333333333°N 96.216666666667°W / 43.383333333333; -96.216666666667
Country United States
State Iowa
FoundedJanuary 15, 1851
Named afterNathaniel Lyon
SeatRock Rapids
Largest cityRock Rapids
Area
  Total
588 sq mi (1,520 km2)
  Land588 sq mi (1,520 km2)
  Water0.1 sq mi (0.3 km2)  0.02%
Population
 (2020)
  Total
11,934
  Density20/sq mi (7.8/km2)
Time zoneUTC−6 (Central)
  Summer (DST)UTC−5 (CDT)
Congressional district4th
Websitelyoncounty.iowa.gov

Lyon County is the most northwestern county of the U.S. state of Iowa. As of the 2020 census, the population was 11,934. The county seat is Rock Rapids.

Lyon County is named in honor of Brigadier General Nathaniel Lyon, who served in the Mexican–American War and the Civil War. He was killed at the Battle of Wilson's Creek, Missouri, on August 10, 1861, after which the county was named for him. The county's name was originally Buncombe County, but was changed by the state legislature on September 11, 1862.