Deildartunguhver (Icelandic pronunciation: [ˈteiltarˌtʰuŋkʏˌkʰvɛːr̥]) is a hot spring in Reykholtsdalur, Iceland.

It is characterized by a very high flow rate for a hot spring (180 liters/second) and water emerges at 97 °C (207 °F).

It is the highest-flow hot spring in Europe.

[a] Some of the water is used for heating; it is piped 34 kilometres (21 mi) away to Borgarnes and 64 kilometres (40 mi) away to Akranes.

A fern called Struthiopteris fallax,[1][2] grows in Deildartunguhver.