The Gudenå or Gudenåen (pronounced [ˈkuˀðn̩ˌɔˀn̩]), is Denmark's longest river and runs through the central parts of the Jutlandic peninsula.

The Gudenåen has its spring in Tinnet Krat, Vejle Municipality (between Nørre Snede and Tørring-Uldum) and flows a total of 149 kilometres (93 mi) to Randers Fjord in Randers,[1] on a northward course which takes it through the central parts of Jutland.

The Gudenåen came into existence some 15,000 years ago, at the end of the last Ice Age, when melting ice and glacial streams carved out its bed.

The river shelters many species of animals and parts of its course are to be protected under the regulations of Natura 2000.

This article related to a river in Denmark is a stub.