In Norse mythology, Mímisbrunnr is the well associated with the wise being Mímir. It lies beneath one of the roots of Yggdrasil and is linked with wisdom and knowledge.
According to Grímnismál, one of the poems of the Poetic Edda, Mímisbrunnr is situated beneath the root of the world tree that extends toward the jötnar. The Prose Edda says that Mímir drinks from the well and that it contains great wisdom. Odin seeks access to this knowledge and sacrifices one of his eyes as the price.
Mímisbrunnr is one of several important wells beneath or around Yggdrasil. Urðarbrunnr is connected with the Norns, while Hvergelmir is associated with primordial waters and the origins of many rivers. These wells are therefore related but not interchangeable.
The name is commonly translated as “Mímir’s well.” Its role helps explain why Mímir is portrayed as a guardian or source of deep cosmic knowledge.