In Irish mythology, Danu is a hypothetical mother goddess of the Tuatha Dé Danann (Old Irish: "The peoples of the goddess Danu"). Though primarily seen as an ancestral figure, some Victorian sources also associate her with the land.
She has possible parallels with the Welsh literary figure Dôn, whom most modern scholars regard as a mythological mother goddess in the medieval tales of the Mabinogion. However, Dôn's gender is never specified in the tales and was regarded as a man by some medieval Welsh antiquarians.
The closest figure in Irish texts to a "Danu" would then be Danand, daughter of Delbáeth. In the Lebor Gabála Érenn: The Book of the Taking of Ireland, it is noted the Tuatha Dé Danann get their name from the three sons of Danand: Brian, Iuchar, and Iucharba. These three are known as the "Gods of Dannan." However, Cormac's Glossary, a text that predates the Lebor Gabala Erenn, names the goddess Anu as the mother of the gods.
Danu and Anu are occasionally described as being the same figure, but their associations indicate that they are probably not the same deity at all. Anu is most commonly associated with the earth (ref: Paps of Anu) whereas Danu is typically associated with rivers and flowing water. Danu has also incorrectly been linked as one of the aspects of The Morrigan.