| Gudenå | |
| Name Other: | The Guden River, Gudenåen |
| Name Etymology: | Gudars stream, Gods stream |
| Map: | Gudena watershed.png |
| Subdivision Type1: | Country |
| Subdivision Name1: | Denmark |
| Subdivision Type3: | Region |
| Subdivision Name3: | Jutland |
| Subdivision Type4: | District |
| Subdivision Name4: | Central Denmark Region |
| Subdivision Type5: | Municipality |
| Subdivision Name5: | Silkeborg, Favrskov, Randers |
| Length: | 149km (93miles)[1] (river) 149 km (inc. Randers Fjord[2]) |
| Discharge1 Avg: | 32.4m3/s |
| Source1 Location: | Tinnet Krat |
| Mouth Location: | Randers Fjord |
| Mouth Elevation: | 0m (00feet) |
| Basin Size: | 3300km2[3] |
| Extra: | Denmark's largest river measured by water volume, the Skjern River, also emerges in Tinnet Krat, close to the source of Gudenå. |
The Gudenå or Gudenåen (in Danish pronounced as /ˈkuˀðn̩ˌɔˀn̩/), is Denmark's longest river and runs through the central parts of the Jutlandic peninsula. An anglicized version of the name often seen is 'The River Guden'.
The Gudenåen has its spring in Tinnet Krat, Vejle Municipality (between Nørre Snede and Tørring-Uldum) and flows a total of 149km (93miles) to Randers Fjord in Randers,[4] on a northward course which takes it through the central parts of Jutland. On its way, the river traverses the relatively high lying region of Søhøjlandet, through the lakes of Naldal Sø, Vestbirk Sø, Mossø, Gudensø, Rye Mølle Sø, Birksø, Julsø, Borre Sø, Brassø, Silkeborg Langsø and Sminge Sø before it empties in Randers Fjord; a long inlet of the Kattegat sea. It is fed by numerous streams and wetlands along the way.
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.