"Mist-home", "Fog-home." One of the nine realms in Norse cosmology, a place of freezing mist that existed before the earth was created. In its midst lies the well called Hvergelmir, the source of the eleven rivers known as the Élivágar. Niflheimr is generally understood to be in the north, separated from the fiery realm of Múspell in the south by the gaping void of Ginnungagap. Cold arose out of Niflheimr, and all terrible things. It lies beneath the third of the three roots of Yggdrasil.
It became domain of Hel, who was cast into Niflheimr by Odin and given power over the nine worlds, to apportion all abodes among those that are sent to her. Below Niflheimr lies Niflhel, which seems to denote the lowest level of hell.
Niflheimr is briefly mentioned in the Icelandic poem Hrafnagaldr Óðins, stanza 26, where it is described as located in the north.
- Gylfaginning, 5, 15, 34.