Nordic Passport Union in the context of Svalbard Treaty

The Helsingør–Helsingborg ferry route ("HH route") is a shipping route connecting Helsingør (Elsinore), Denmark and Helsingborg, Sweden across the northern, and narrowest part of the Øresund. Due to the short distance, which is less than 3 nautical miles, it is one of the world's busiest international car ferry routes, with around 70 daily departures from each harbour. The oldest-known written mention of the route dates to the German traveller Adam of Bremen in the 11th century, but it has likely been in use much longer. Before 1658, the route was a domestic Danish route. For several centuries, the route has been run regularly by various Danish shipping lines. Its significance grew during the 1950s, but since the inauguration of the Øresund Bridge in 2000, at the southern end of the Øresund, it has lost some significance but remains as one of the world's most important ferry routes, particularly as a cheaper alternative to the bridge tolls. Since 1952, passports have not been required for citizens of the Nordic Passport Union countries. Since 2001, when both countries became members of the Schengen Area, passports are not needed for anyone.

The Finland–Sweden border (or Finnish–Swedish border) is the border between the countries of Finland and Sweden. Almost the entire border runs through water: along the Tornio River and its tributaries, and in the Gulf of Bothnia. Only a few kilometres of the border are on dry land. Because of the Schengen treaty and the Nordic Passport Union, the border can be crossed mostly freely.