Though the castle itself no longer survives in its original form, its strategic position overlooking the river tells us much about the defensive considerations of medieval Irish lords. Just northeast across the water, visitors can spot Poulnalong Tower House, creating what would have been a formidable pair of fortifications controlling this stretch of the Bandon.

This castle was once a stronghold of the MacCarthy Riabhach branch of the MacCarthy dynasty, one of the most powerful Gaelic families in Munster during the medieval period. The MacCarthys controlled vast swathes of territory across Cork and Kerry, with different branches of the family establishing their own castles and tower houses throughout the region. The Riabhach, or ‘grey’ MacCarthys, were particularly influential in this part of County Cork, where they maintained several fortifications to protect their lands and assert their authority.

The riverside location was no accident; controlling the Bandon meant controlling trade, travel, and communication through this part of West Cork. Medieval castles like Carrighnassig weren’t just military installations but centres of administration and commerce, where rents were collected, justice was dispensed, and the business of lordship was conducted. Today, while the castle may be gone, the site remains an evocative reminder of how the landscape itself shaped the politics and power structures of medieval Ireland.