The Hill of Uisneach in Co. Westmeath has played a part in just about every significant Irish event, be it political, cultural, religious, mythological and geographical. The centre of Ireland in many ways, the enigmatic hill is one of the most sacred and historic sanctuaries in the world.
The roots of Uisneach lie beyond recorded history but its surviving monuments and relics range in date from the Neolithic, early Bronze Age to the medieval period, indicating human activity spanning some five millennia.
The burial site of the Earth Goddess Ériu & the Sun God Lugh and as such was regarded as sacred ground. Uisneach was seen as a gate to the mythical fifth province, Mide, which held the four more familiar provinces together. For centuries, the fifth province was accessed at ‘Aill na Mireann’ (the Stone of Divisions) a sacred, fissured and fragmenting limestone boulder on the south west slope of the Hill. A Glacial erratic, this huge six metre, thirty tonne boulder symbolises Ireland united in its divisions. It has also been known as ‘Umbilicus Hiberniae’, ‘Axis Mundi’, and ‘the Naval of Ireland’. Today, it is the most famous of over forty surviving features on Uisneach, although it is more commonly known as the ‘Catstone’, named so because it resembles a cat watching a mouse. It is under the ‘Catstone’ that Ériu is resting.
Uisneach became the seat of the High Kings in later years and ancient texts state it became customary for the claimant to the high throne of Ireland to ‘marry’ Ireland’s founder Ériu at a ceremony on Uisneach. It was said in ancient times that Uisneach divided Ireland into ‘knowledge in the West, battle in the North, prosperity in the East, music in the South and Royalty at the Centre.’ When Tara later became the seat of the High Kings, Uisneach was still the royal centre of Ireland – the meeting point of the ancient provinces where laws were struck and divisions agreed. It was linked to Tara by a ceremonial road, a section of which remains today.
Content from http://uisneach.ie/history/