Strokkur is a fountain-type geysir located in a geothermal area beside the Hvítá River. Its usual height is 15–20 metres (49–66 ft), although it can sometimes erupt up to 40 metres (130 ft) high.
Strokkur is only 50 meters from Great Geysir, but unlike Great Geysir, which is active very rarely and can lie dormant for several years, Strokkur erupts every 4-6 minutes, releasing water up to 40 meters into the sky.