Amager, located in the Øresund, is Denmark's most densely populated island, with more than 216,000 inhabitants. The protected natural area of Naturpark Amager makes up more than one-third of the island's total area of 96 km2.

Øresund or Öresund, commonly known in English as the Sound, is a strait which forms the Danish–Swedish border, separating Zealand (Denmark) from Scania (Sweden). The strait has a length of 118 kilometres (73 mi); its width varies from 4 kilometres (2.5 mi) to 28 kilometres (17 mi). The narrowest point is between Helsingør in Denmark and Helsingborg in Sweden.