European route E 4 passes from north to south through Sweden from the border with Finland, with a total length of 1,590 kilometres (990 mi). The Finnish part lies entirely within Tornio in northern Finland, and is only 1 kilometre (0.62 mi) long. The Swedish part traverses most of Sweden except the extreme north and the west coast region, and is commonly considered the highway backbone of Sweden, since it passes in the vicinity of many of its largest cities and through the capital Stockholm. In particular, it is the mainline road used by most vehicle traffic, both personal cars and freight trailers, between the north (Norrland) and southern Sweden or beyond.
From Haparanda on the Finnish border, it stretches south along the Gulf of Bothnia to Gävle, then on a more inland route southwards. It ends in Helsingborg in Sweden, at the port for the ferry to Helsingør in Denmark. The route intersects with European route E6 just outside Helsingborg, which continues to Trelleborg on the southern coast of Sweden.