Rjukan is a town and the administrative centre of Tinn municipality in Telemark, Norway. It is situated in Vestfjorddalen, between Møsvatn and Tinnsjå, and got its name after Rjukanfossen ("The Smoking Waterfall") west of the town. The Tinn municipality council granted township status for Rjukan in 1996. The town has 3,386 inhabitants (Jan.