What is the name of the well of fate at the root of Yggdrasil?

The well of fate at the root of Yggdrasil is Urðarbrunnr.

Urðarbrunnr, whose name means “Urðr’s well” or “well of fate,” lies beneath one of the roots of Yggdrasil, the sacred world tree. It is associated with the three Norns—Urðr, Verðandi, and Skuld—who shape or determine the lives and destinies of gods and humans.

The well appears in both the Poetic Edda and Snorri Sturluson’s Prose Edda, texts written down in the 13th century from older traditions. In the Prose Edda, the gods travel to Urðarbrunnr each day to hold court. The Norns also draw water from it and use the water and surrounding mud to protect Yggdrasil from decay.

Urðarbrunnr is often confused with the other important wells beneath Yggdrasil’s roots. Hvergelmir is linked with Niflheim and the dragon Níðhöggr, while Mímisbrunnr contains wisdom and is associated with Mímir. The specific “well of fate” description points to Urðarbrunnr.