Stuðlagil is a ravine in Jökuldalur in the municipality of Múlaþing, in the Eastern Region of Iceland. It is known for its columnar basalt rock formations and the blue-green water that runs through it. It became an unexpected tourist sensation after being shown in a WOW air brochure in 2017. The rock formation is 30 meters tall. The river Jökla runs through the ravine. The water level decreased by 7 to 8 meters after the opening of the Kárahnjúkar Hydropower Plant in 2009.