[2] According to historian C. Thomas Cairney, the O'Dunnes were one of the chiefly families of the Ui Failghe who in turn were a tribe from the Dumnonii or Laigin who were the third wave of Celts to settle in Ireland during the first century BC.
Originally known as "Baun Riaganach", the castle was built by Tadhg MacLaighnigh Ui Duinn in 1475 and was the residence of the chief of the Dunne's.
Tinnahinch Castle was destroyed by during the Cromwellian Invasion by forces led by Colonel John Hewson in 1653.
At the time it was strongly defended by Charles Dunne and it required a full park of artillery from the invading forces to level the castle.
After the destruction of Tinnahinch Castle the Dunne Chief built a new home at Brittas, near Clonaslee, County Laois.
It was built by Colonel Terence O'Dunne in 1680 who was killed at the Battle of Aughrim and is buried at the graveyard in Killeigh.
The Dunnes also built Ballinahemmy Castle near the town of Corrigeen, in County Laois, and its location is marked on the Ordnance Survey map.