The castle formed part of a defensive pair with another tower on the opposite end of the bridge, both strategically positioned to control movement along this vital waterway. By the time of the Civil Survey of 1654-6, the structure was already recorded as ruins alongside its barbican, with Donogh O’Bryen listed as its proprietor in 1640.

When Ordnance Survey inspectors visited the site in 1840, they found only fragments of what had once been an imposing square tower. The eastern wall still stood to a height of about 24 feet, with portions of the north and south walls clinging to it; 10 feet of the southern wall and 7 feet of the northern wall remained. The castle’s original footprint measured approximately 33 feet 6 inches by 23 feet externally, with impressively thick walls of 7 feet constructed from well-grouted stone. Two rectangular windows survived at that time, one each in the east and south walls, both crafted from carefully chiselled brown sandstone. A spiral staircase had once occupied the south-east corner, typical of tower houses of this period.

The castle was historically associated with the Mac Ibrien Ara family, one of the local Gaelic lordships who controlled this region during the medieval period. Today, no visible remains of Ballina Castle survive; modern housing development has completely transformed the area where this once-mighty fortress stood watch over the Shannon. Archaeological testing conducted in 2001 at the rear of the Old Dispensary in Ballina village revealed no features related to the castle, suggesting that centuries of development have thoroughly erased this piece of medieval heritage from the landscape.