Trim Castle is a Norman castle located on the south bank of the River Boyne in Trim, County Meath.
With an area of 30,000 m², it is the largest Cambro-Norman castle in Ireland.
Over a period of 30 years, it was built by Hugh de Lacy, Lord of Meath and his son Walter as the caput of the Lordship of Meath.
The Castle was used as a centre of Norman administration for the Lordship of Meath
This was one of the new administrative areas of Ireland created by King Henry II of England.
Hugh de Lacy took possession of it in 1172 and built a huge ringwork castle defended by a stout double palisade and external ditch on top of the hill.
Reference: Wikipedia