The line originally split from the Meråker Line at Hell Station 31 kilometres (19 mi) north of Trondheim, but this stretch has been reclassified by the Norwegian National Rail Administration as part of the Nordland Line. After Hell the railway passes through the towns of Stjørdal, Levanger, Verdal, Steinkjer, Mosjøen, Mo i Rana and Fauske before reaching Bodø. The line has three branch lines: the Meråker Line (to Sweden), the Namsos Line and Sulitjelma Line. The latter two are currently disused and the Sulitjelma Line has been removed.
Unlike most of the Norwegian rail network, the Nordland Line is not electrified. Passenger traffic is fairly heavy between Trondheim and Steinkjer through the Trøndelag Commuter Rail, but is significantly lighter further north. Most passenger services are provided by diesel multiple units (DMU), while the night train service, conveying sleeping cars is locomotive-hauled. The use of DMUs on Norway's longest railway route has been somewhat controversial, given the lower level of comfort offered by this type of train. In February 2007, NSB announced reintroduction of traditional locomotive-hauled trains for the full distance day train.
There is fairly heavy iron ore transport between the mine at Storforshei and Mo i Rana, 35 km. There are plans to upgrade the track quality here in order to allow heavier trains.
The first part of the route towards Bodø, from Trondheim to Hell, was opened in 1882 as part of the Meråker Line, which links Trondheim to the Swedish border and the Swedish railway system (Central Line). The new Hell–Sunnan Line was built branching off from the Meråker Line reaching Levanger in 1902, Verdal in 1904 and Sunnan in 1905. It subsequently reached Snåsa in 1926 and Grong in 1929. The branch line from Grong to Namsos, the Namsos Line, was opened in 1933. Before the German invasion of Norway in 1940, the Nordland Line had reached Mosjøen. Construction continued under German supervision during the war, and by 1945 it had reached Dunderland. The section to Fauske opened in 1958 and the final part to Bodø opened in 1962. During the occupation Germany forces started building an extension of the railway from Fauske to Narvik, the Polar Line, but this was never completed during the war, and abandoned by Norwegian authorities afterwards.