The origins of Uisneach lie far beyond recorded history with surviving monuments and relics dating from the Neolithic (3700-2500 BC) and Bronze Ages (2500-500 BC) which confirm its ceremonial status in pre-historic times. In early written sources, the area in which Uisneach is located, is recorded as 'Mide', meaning 'middle'. Originally a name for the hill itself (i.e. Uisneach Midi, the 'temple' or 'hearth' at the centre), over time the territory expanded to become the medieval Kingdom of Mide which gives its name to the modern counties of Meath & Westmeath. In the first millennium AD, Uisneach became the chief palace and assembly site of the Clann Cholmain kings, who ruled over the Kingdom of Mide with some even becoming High Kings of Ireland. The last of these was Máel Sechnaill Mór, who became High King in 980. His reign lasted until 999, when Brian Boru came to Uisneach to claim sovereignty over Mide and ultimately the High Kingship of Ireland. In the 19th and early 20th Centuries, Uisneach was the site of great political rallies, with Daniel O'Connell and Eamonn De Valera addressing huge crowds from atop the Ail na Míreann.

Since pre-Christian times the hill has been regarded as the ceremonial & sacred centre of Ireland; the meeting point of the ancient provinces, where laws were struck and divisions agreed. In later years, when Tara became the political seat of the High Kings of Ireland, Uisneach retained its position as the country's spiritual centre. Uisneach also plays a central role in Irish mythology. The hill is said to be the burial place of both Ériu, the Sovereignty Goddess, after whom Ireland is named, & Lugh, the heroic God-King of the Tuatha dé Danann. The summit of the hill is also where The Dagda, father of the gods, is said to have made his home, with "Ireland stretching equally far from it on every side, to south and north, to east and west".