Stuðlagil is a canyon located in Jökuldalur in the municipality of Múlaþing, in the Eastern Region of Iceland.
Stuðlagil formed by the Jökulsau-au-Brü river. It is known for its columnar basalt rock formations and the blue-green water that runs through it. The height of the walls is up to 30 m (98 ft).
After the opening of the Kaurahnjukar hydroelectric power station in 2009, the water level in the river decreased by 7-8 meters (23 to 26 ft) and so the walls was appeared for looking.