For several thousand years, a sandy tongue of land has made up the border between the North Sea and the inlet of Limfjorden. In 1862, the sea broke through the tongue of land by Thyborøn and created what is now known as the passage of Thyborøn Kanal – the outlet of Limfjorden into the North Sea. Today, human-made coastal protection, sluices and dikes are needed to make sure that Harboøre Tange is stable enough for the fishing and sea port of Thyborøn to be safe. Harboøre Tange was registered as protected in 1984 and this area is known as one of the most important meadow bird areas in Denmark.
