Writing in 1837, Lewis observed that the castle had already been reduced to this single slender tower, which according to later surveys rises about 25 feet (8 metres) high and contains a spiral staircase winding to its top. Despite its diminished state, this tower offers a tangible link to centuries of turbulent Irish history.

The castle's documented history stretches back to at least 1452, when it appeared in records as 'Ballyeghn', a property of the influential Desmond family. The fortification changed hands numerous times through rebellion and royal decree. In 1583, Peter Wall held the castle but met his end on the executioner's block after joining the Earl of Desmond's rebellion against English rule. Four years later, the Crown granted it to Oliver Stephenson, having confiscated it from Ulick Wall, known as "The Falltach". The castle continued to pass through various owners including F. Trenchard in 1598, Sir E. Berkeley in 1612, and J. Hurley in 1655, before being granted to the Duke of York in 1665.

These frequent changes in ownership reflect the broader patterns of land confiscation, rebellion, and plantation that characterised Irish history during this period. The castle at Ballyegny Beg, though now reduced to a single tower, served as both a defensive structure and a symbol of authority in the volatile political landscape of medieval and early modern Limerick.