formerly Glåma River
River, eastern Norway.
The longest river in Scandinavia , it rises in a series of small streams near the Swedish-Norwegian border. It flows south, then west into Lake Øyeren. From there it continues south to Sarpsborg and enters Oslo Fjord at Fredrikstad, after a course of 372 mi (599 km). It is a major source of hydroelectric power. It is navigable up to Sarpsfoss, the waterfall at Sarpsborg.