Former populated places in Denmark

thumb|North Frisian coastline before 1362 thumb|The island of Strand (island)|Strand after the Grote Mandrenke (Danish: Den Store Manddrukning) with German and Danish place names thumb|Rungholt and Strand in the Middle Ages, on a map from 1850 Rungholt was a low-lying settlement in North Frisia, in what was then the Danish Duchy of Schleswig. The area today lies in Germany. Rungholt was flooded, with massive erosion, when a storm tide (known as Grote Mandrenke or Den Store Manddrukning) hit the coast on 15 or 16 January 1362.

iron- and viking age grave yard in Denmark

Fyrkat is a former Viking ring castle in Denmark, dating from c. 980 AD. It is located near the town of Hobro, some distance from the present end of the Mariager Fjord in Northern Jutland. The fortress is built on a narrow piece of land, with a stream on one side and swampy area on the other sides. Likely built during the reign of Harald Gormsson or his son Sweyn Forkbeard, the fortress may have served as barracks or as a defensive stronghold. It would have help to enable control of the traffic on the main land-based trading route between Aalborg and Aarhus. Because of its unique architecture

thumb|200px|Sentinel-2 image of Jordsand Jordsand () was a small Danish hallig located in the Wadden Sea southeast of the Danish island Rømø and east of the German island Sylt. The island was first known by the name Hiortsand ("hart island") and was possibly connected to both the mainland and the island of Sylt. The old name refers to the presence of deer on the island.

Borremose is a raised bog in central Himmerland, Denmark south east of the town of Aars. The name translates directly as 'Borre'-bog, where 'Borre' might well be a derivation of the old word burgh meaning fortified place, as seen in many other place-names.

Eidum or Eydum (, North Frisian: Eidem) was a historic place on the German (former: Danish) island of Sylt in the North Sea. It was several hundred metres west of the present coast line of the present-day village of Westerland.