Peberholm lies approximately 1 km south of the larger natural island of Saltholm (Salt Islet) and was named to complement it.

The tunnel was built since a bridge spanning the entire link between Malmö and Copenhagen would have interfered with obstacle-free zones around Kastrup Airport.

Making the Øresund Bridge higher would have interfered with the freight train traffic because a steeper gradient would be needed.

They required either the construction of both a motorway and railway across Saltholm or an expansion of the existing island to serve the same purpose.

The location was chosen in the belief that it would ensure the freest flow of water through the strait, a key element in the debate about whether or not the bridge should be constructed.

Scientists predicted that nature would colonise it and make the island flourish on its own, without any human interaction whatsoever.

Many geese, ducks, great cormorants, and waders rest on the small island and the white-tailed eagle is often observed in winter.

This is considered a relatively low diversity compared to similar habitats in Denmark and Sweden, however some of these species are rare or threatened in the region.