The oldest parts of this castle probably date from the early thirteenth
century, its builder most likely was Gerald fitz Maurice. The castle
was burned in 1316 during the Bruce invasion. It was captured by
Cromwell's army in 1650.
The keep is rectangular with round cornered towers, of which only
one is almost complete. The curtain wall and twin towered gate house
were probably added in the late thirteenth century.
Ballaghmore was built in the fifteenth century
by the Fitzpatrick's Lords of Upper Ossary, it was strategically
placed beside one of the roads of ancient Ireland which pass through
the Slieve Bloom Mountains. The castle was sieges several times
finally falling to Cromwell in 1647. The dead from the defeated
garrison were said to have been buried in a circular grave near
the castle on which nothing would grow.
The castle was then granted to the Coote
family later to become earls of Mountrath, it remained in their
possession until the middle of the nineteenth century, when they
sold the estate to the Ely family