Allen County, Kansas

Allen County, Kansas
Location within the U.S. state of Kansas
Country United States
State Kansas
FoundedAugust 25, 1855
Named afterWilliam Allen
SeatIola
Largest cityIola
Area
 • Total
505 sq mi (1,310 km2)
 • Land500 sq mi (1,300 km2)
 • Water5.0 sq mi (13 km2)  1.0%
Population
 (2020)
 • Total
12,526
 • Density25.1/sq mi (9.7/km2)
Time zoneUTC−6 (Central)
 • Summer (DST)UTC−5 (CDT)
Area code620
Congressional district2nd
WebsiteAllenCounty.org

Allen County is a county located in the southeast portion of the U.S. state of Kansas. Its county seat and most populous city is Iola. As of the 2020 census, the population was 12,526. The county was named for William Allen, a U.S. Senator from Ohio and prominent supporter of westward expansion.