Urriðafoss (Icelandic pronunciation: [ˈʏrːɪːðaˌfɔsː], "sea trout waterfall") is a waterfall located in the river Þjórsá in southwest Iceland.

[1] The Fossafélagið Títan company was given permission in 1927 to build a power plant in Urriðafoss in connection with a railway to Reykjavík from the waterfall.

[2] It did not happen but now Landsvirkjun is planning to build hydropower stations on the lower part of Þjórsár river, at Urriðafoss and Núpur.

The waterfall is expected to disappear if the powerhouse is built.

Local residents in the area are protesting against the construction in an effort to save Urriðafoss.