The Dal River (Swedish: Dalälven) is a river in central Sweden that flows from the north of Dalarna and runs into the sea in northern Uppland; it is commonly considered to be the southern border of Norrland, however only the last part correlates with Limes Norrlandicus (the biological Norrland border).

The biosphere reserve benefits from a highly participatory governance system as well as numerous partnerships with universities and research centres for environmental monitoring.

It extends 541 kilometres (336 mi) between the mountains of Dalarna and the Baltic Sea, which makes it the second longest river in the country after the Göta älv.

[6] After their confluence, the river enters into a series of narrow lakes (Idresjön, Alvrosfjorden, Kringelfjorden, Hedfjorden, Särnasjön, etc.).

[7] The river then arrives at Mora where it receives the waters of the Oreälven, one of its major tributaries[1] and empties itself immediately after into the Lake Siljan, the largest lake in the entire catchment area, and the seventh largest in all of Sweden, with a surface area of 292 kilometres (181 mi).

[8] This lake is formed by the largest impact crater in western Europe, of a diameter of 75 kilometres (47 mi).

After the confluence this river continues south, passing Sälen and then Malung and forking east to arrive in Vansbro Municipality.

At that time, the Lower Dalälven was below sea level and was in the zone corresponding to today's Dalarna, which was the first area settled.

An important factor behind it was the 1607 prohibition from Charles IX of cutting wood closer than one Swedish mile from Falun Mine.

However, until the Storskiftet land amalgamation reform and England's abolition of customs on wood products in 1849, the logging stayed small-scale.

[15] Four major sawmill companies dominated the logging in River Dalälven: Korsnäs AB at Lake Runn (Falun), established in 1858; Kopparbergs och Hofors Sågverks Bolag at Lake Hosjön (Falun), which started in 1861 and bought its competitor Carlfors Sågverksbolag in 1874; Stora Kopparbergs Bergslags AB, which modernized its mill at the rapids of Domnarvet (Borlänge) in 1863; and the mill in Älvkarleby, which was replaced by Skutskär sawmill in 1870.

[15] In The Wonderful Adventures of Nils, Swedish author Selma Lagerlöf dedicates a chapter to the river.

During the race, these rivers receive help from many tributaries, but also encounter many obstacles (lakes to fill, hills to pierce, etc.