The Allen County Seat is Iola, a four letter word. Iola is a city located in Allen County, Kansas, United States. It is the county seat of Allen County and has a population of 5, 704 people as of the 2010 census. Iola is known for its historic downtown district, which includes several buildings listed on the National Register of Historic Places. The city is also home to the Allen County Historical Museum, which houses artifacts from the area's history.