The island is situated in the so-called Königshafen (King's Harbour), a bay on the eastern shore of Sylt which is facing the shallow tidal flats of the Wadden Sea in that area.

Uthörn is located north of the town of List, only a kilometre away from the Ellbogen (Elbow) peninsula of Sylt, which is Germany's northernmost area.

The island is overgrown by pioneer species of plants and the common dune vegetation like marram grass.

Uthörn is located just a few metres off the shore of Sylt and can be reached on foot through the shallow sea.

But as it provides space for the hatching and resting of rare and endangered seabirds and is situated inside the Schleswig-Holstein Wadden Sea National Park, it may only be entered with special permission.