Alrø is a small Danish island in Horsens Fjord on the east coast of Jutland within Odder Municipality.The island is 7.52 km long with a coastline of 14 km, and stretches a little over 5 km wide from east to west. With a population of 147 as of January 2013, the island can be reached by road over an artificial causeway which connects it to the mainland on the northern side of the fjord.