Øresund (örəsŭndˈ) [key] or the Sound, Swed. Öresund, c.45 mi (70 km) long, strait between the Danish island of Sjælland and Sweden, connecting the Kattegat with the Baltic Sea, to which it is the deepest channel. Between Helsingborg and Helsingør it is only 2.5 mi (4 km) wide. Copenhagen and Malmö are on the Øresund. A strategic passage, control of the strait was long contested between Denmark and Sweden. A bridge-tunnel link across the strait, connecting Copenhagen and Malmö, opened in 2000.
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