Corydon is a city in Wayne County, Iowa, United States. The population was 1,526 in the 2020 census, a decline from 1,591 in 2000. It is the …Corydon is a city in Wayne County, Iowa, United States. The population was 1,526 in the 2020 census, a decline from 1,591 in 2000. It is the county seat of Wayne County. The town was laid out and platted in 1851 and later that year designated as the county seat. The town was named by county judge Seth Anderson after his old hometown of Corydon, Indiana.