The River Guden (Danish Gudenåen, ), on the Jutland peninsula,'s Denmark's longest. It flows 176 kilometres from Tinnet Krat in Vejle County, between Nørre Snede and Tørring-Uldum, to Randers Fjord in Randers, on a course which takes it through central Jutland. On its way it traverses the lakeland waters of Sminge Sø (Lake Sminge), Silkeborg Langsø, Brassø, Borre Sø, Julsø, Biksø, Rye Mølle Sø, Gudensø, Mossø, Vestbirk Sø, an… (More on Gudenaa)