Rjukan was formerly a significant industrial centre in Telemark, and the town was established between 1905 and 1916, when Norsk Hydro started saltpetre (fertilizer) production there.
Rjukan je nekada bio značajno industrijsko središte u Telemarku, a grad je osnovan između 1905. i 1916. godine, kada je tvrtka Norsk Hydro tamo započela proizvodnju salitre (gnojiva).