Ærø Municipality is a kommune occupying the 88 km² island of Ærø in Denmark in the Region of Southern Denmark as of 1 January 2007, …Ærø Municipality is a kommune occupying the 88 km² island of Ærø in Denmark in the Region of Southern Denmark as of 1 January 2007, and in 2006 in Funen County. The municipality also encompasses Birkholm and the uninhabited islands Lilleø, Dejrø and Halmø.