In Norse mythology, the Elivagar are eleven venomous frozen rivers. They flow out of Hvergelmir, a spring at one of the roots of the world tree Yggdrasil, into Ginnungagap, the cosmic abyss. From their frozen waters, the giant Ymir sprang to life.
The names of the rivers are listed in Snorri Sturluson's Poetic Edda: Svol, Gunnthra, Fjorm, Fimbulthul, Slid, Hrid, Sylg, Ylg, Leipt, Gjoll and Vid.
The name of the river Gjoll was borrowed by Gene Wolfe for his science fiction series The Book of the New Sun.