Jökulsá (yö'külsou), name of several Icelandic rivers formed by glaciers. The best known is the Jökulsá á Fjöllum, which rises on the north slope of the Vatnajökull in SE Iceland and flows c.130 mi (210 km) N into the AxarfjörÐur, forming the Dettifoss c.30 mi (50 km) from its mouth.




