The grant included the castle, town and lands of Clonagannagh, which was formally established as the manor of Clonageneth. This wasn’t merely a land transfer; O’Carroll received substantial legal powers, including the right to create 500 acres of private demesne lands and to hold both courts leet and baron, effectively making him the judicial authority for the area. These manorial courts handled everything from petty crimes to land disputes, giving O’Carroll considerable influence over local affairs.

The original Clonagannagh Castle appears on the Down Survey maps from 1654 to 1657, one of the most comprehensive land surveys ever undertaken in Ireland. Created in the aftermath of the Cromwellian conquest, these maps provide a rare glimpse of the Irish landscape during a period of dramatic change. The castle’s exact fate remains uncertain, though it likely suffered the same destruction that befell many Irish fortifications during the turbulent 17th century.

Today, a house known locally as ‘the stump house’ stands to the east of Alley’s Bridge on the south side of the road, and archaeological evidence suggests it may occupy the site of the original Clonagannagh Castle. The nickname likely refers to its truncated appearance or perhaps to remnants of the earlier structure incorporated into its construction. While the grand manor courts and extensive lands granted to O’Carroll have long since disappeared into history, this modest building serves as a tangible link to a time when this corner of Offaly was a seat of considerable local power.