Ærø is a narrow Danish island in the Baltic Sea. Ærø measures roughly 20 km from northwest to southeast and varies in width from around 4 to 8 km. There are three small towns on the island: the largest is Marstal with a population of 2,266. Ærøskøbing has 925 inhabitants and Søby 496. Fourteen villages and a number of farms complete the island's pattern of settlement.