In Irish mythology, Uisneach is described as the sacred centre of Ireland, the burial place of Irish gods such as Lugh and the Dagda, the site of a sacred tree (the Bile Uisnig), and a place of assembly (the mórdáil Uisnig) associated with the druids, which, according to later tradition, was held during the festival of Bealtaine. The Ail na Míreann ("stone of the divisions") in particular is described as the navel of Ireland. It is seen as a kind of omphalos or axis mundi of Ireland, a meeting place between the Earth and the Otherworld and the source of creation. It is said to have marked the meeting point of the provinces.
Hill of Uisneach is known as the naval of Ireland because of its central location. It has also been called the “heart chakra of Ireland” for generations.
The Dindsenchas ("lore of places") says that Uisneach is where the druid Mide lit a sacred fire that blazed for seven years. The tale Tucait Baile Mongáin ("Mongan's Frenzy") describes how a great hailstorm during an assembly on the hill created the twelve chief rivers of Ireland. In the Lebor Gabála Érenn ("Book of the Taking of Ireland"), the Gaels (Milesians) meet the goddess Ériu at Uisneach where, after some conversation and drama, the Milesian poet Amergin promises to give the land her name. She is said to be buried under the Ail na Míreann.
In mythology, Uisneach and Hill of Tara are said to be linked. In the literature, Tara is mainly associated with royal power, while Uisneach is mainly associated with spiritual power. Anciently, both locations had festivals or meetings every seven years – the Feast of Tara at Samhain and the Great Meeting of Uisneach at Beltane; at the Feast of Tara new laws were passed and councils formed. It was linked to Tara by the ancient road called the Slighe Assail; the modern R392 road mostly follows its route.
The tragic tale of Deirdre and the "sons of Uisnech" or "sons of Uisliu" (Naisi, Ardan and Ainle) is part of the Ulster Cycle of Irish mythology.
Geoffrey of Monmouth's Historia Regum Britanniae ("History of the Kings of Britain") says that Stonehenge originally stood at the 'hill of Killare' (mons Killaraus) in Ireland, before being moved to Britain. This is thought to refer to Hill of Uisneach, as Killare is a place at the foot of the hill.