Symbol reference · Galdrastafir
Bifröst
/ˈbɪvrɒst/Old Norse Bifröst, feminine noun; also Bilröst, and Ásbrú, 'the Æsir's bridge'
The short answer
The bridge the gods built from earth to heaven, which people see as the rainbow. Snorri says it has three colours, that the red in it is burning fire, that the gods ride over it every day to their court at the well of Urðr, and that it will break at Ragnarök.
When Gangleri asks what road leads from earth to heaven, Snorri's High One laughs at the question: the gods built a bridge from earth to heaven called Bifröst, 'you will have seen it, and perhaps you call it the rainbow'. It has three colours and is very strong, made with more skill than any other work. Strong as it is, it will break when the sons of Múspell ride over it at Ragnarök.
The bridge is also called Ásbrú, 'the Æsir's bridge'. Every day the Æsir ride up over it to hold their court at the well of Urðr, beneath the third root of the world tree Yggdrasil. Thor goes on foot instead, wading the rivers Körmt and Örmt and the two Kerlaugar, because, in the verse Snorri quotes from Grímnismál, the Æsir's bridge burns all in flame. When Gangleri asks whether fire burns over Bifröst, the High One answers that the red you see in the bow is burning fire: if everyone who wanted to could cross Bifröst, the frost giants and mountain giants would climb into heaven.
Its guard is Heimdall, who lives at Himinbjörg at the bridge's heavenly end, sees by night as well as by day and hears grass grow. The Eddic poems Grímnismál and Fáfnismál use the form Bilröst, and scholars still argue over which name came first and what exactly each means.
The bridge is also called Ásbrú, 'the Æsir's bridge'. Every day the Æsir ride up over it to hold their court at the well of Urðr, beneath the third root of the world tree Yggdrasil. Thor goes on foot instead, wading the rivers Körmt and Örmt and the two Kerlaugar, because, in the verse Snorri quotes from Grímnismál, the Æsir's bridge burns all in flame. When Gangleri asks whether fire burns over Bifröst, the High One answers that the red you see in the bow is burning fire: if everyone who wanted to could cross Bifröst, the frost giants and mountain giants would climb into heaven.
Its guard is Heimdall, who lives at Himinbjörg at the bridge's heavenly end, sees by night as well as by day and hears grass grow. The Eddic poems Grímnismál and Fáfnismál use the form Bilröst, and scholars still argue over which name came first and what exactly each means.
Primary source Verbatim
Er þér eigi sagt þat, er goðin gerðu brú af jörðu til himins, er heitir Bifröst? Hana muntu sét hafa. Kann vera, at þat kallir þú regnboga. Hon er með þrimr litum ok mjök sterk [...]
Have you not been told that the gods built a bridge from earth to heaven, called Bifröst? You will have seen it. It may be that you call it the rainbow. It has three colours and is very strong [...]
GYLFAGINNING, ch. 13 · translation editorial ↗
Etymology
Bifröst
Old Norse
bifask, 'to shake, tremble', and röst, a 'league' or stretch of road, read here as 'way'; so perhaps 'the trembling (or swaying) way'
Bilröst
Old Norse
the form in the Eddic poems; bil, 'moment' or 'weak point', and röst; perhaps 'the fleeting way'
Both forms end in röst, a 'league' of road, usually read here as 'way'. Which one is older, and what the first element meant, is still debated.
Common misconceptions
Common claim
What the record says
“Bifröst is a rainbow of many colours.”
Snorri says it has three colours, and that the red is burning fire. He identifies it with the rainbow, but he does not give it the seven colours of the modern spectrum.
“Bifröst links the Nine Realms to each other.”
In Snorri it runs from earth to heaven only, and the gods use it to ride to their court at the well of Urðr. Bifröst as a hub joining all nine worlds is a modern idea.
“Bifröst is a teleporter or a beam of light.”
That is the Marvel version. In the sources it is a bridge that gods ride across on horseback, strong but destined to break under the sons of Múspell.
Frequently asked questions
What is Bifrost in Norse mythology?
The bridge the gods built from earth to heaven. Snorri says people see it as the rainbow, that it has three colours, and that it will break at Ragnarok when the sons of Muspell ride over it.
Who guards Bifrost?
Heimdall, the watchman of the gods, who lives at Himinbjorg where the bridge reaches heaven and guards it against the giants.
Why is Bifrost red?
Snorri says the red you see in the bow is burning fire, and that if anyone who wished could cross, the frost giants and mountain giants would climb into heaven.
Does Thor use Bifrost?
What happens to Bifrost at Ragnarok?
It breaks when the sons of Muspell ride across it. Snorri says nothing in the world can be trusted once they go to war. More in our Bifrost article.
Is it Bifrost or Bilrost?
Both. Snorri uses Bifrost, while the Eddic poems Grimnismal and Fafnismal have Bilrost. Scholars still debate which is older.
Bibliography
- 1. Snorri Sturluson, Edda (Gylfaginning 13, 15, 17, 27 and 51), c. 1220. Trans. Anthony Faulkes, Everyman, 1987. heimskringla.no ↗
- 2. The Poetic Edda (Grímnismál 29 and 44; Fáfnismál 15), Codex Regius, GKS 2365 4to, c. 1270. Trans. Carolyne Larrington, rev. ed., Oxford World's Classics, 2014. handrit.is ↗
- 3. Rudolf Simek, Dictionary of Northern Mythology, trans. Angela Hall, D. S. Brewer, 1993, s.v. 'Bifröst'.
Cite this entry
VikingsBrand. “Bifröst.” VikingsBrand Library, reviewed 30 September 2026, vikingsbrand.co/pages/library/bifrost.