Mandø is one of the Danish Wadden Sea islands off the southwest coast of Jutland, Denmark in the Wadden Sea, part of the North Sea. The island covers an area of 7.63 km² and has 62 inhabitants. The island is situated approximately 12 kilometers southwest of the ancient town of Ribe.Mandø is barely accessible at high tide over an unpaved surface level causeway of about four kilometers in length that connects the island to the mainland. Extensive mudflats and tidal marshes encircle the island and provide breeding areas to multitudes of birds and other organisms.
Conventional motor vehicles can access Mandø Island via a causeway unpaved roadway, although this route is compromised in storms at high tide. The nearest village on the mainland which is the gateway to Mandø Island is Vester Vedsted.Mandø is geographically one of the northernmost islands among the North Frisian Islands off the southwestern Danish and northwestern German coast.The principal ecosystems on this island are: tidal marsh; mudflat; littoral zone; and upland grassland. In fact, there is about as much land area in mudflat as the considerable arable land of the island. Mandø Island is known for its extensive birdlife.