The castle ruins occupy a roughly square area about 46 metres across, enclosed by a partially surviving bawn wall that now serves as a farmyard complete with modern sheds and abandoned 19th century farm buildings. The western and northern walls stand the tallest at 4 to 5 metres high, whilst much of the southern and eastern sections have been removed over time. At the southwest corner, traces of what may have been the main hall survive; a rectangular structure measuring approximately 17 by 10 metres, with walls that grow notably thicker at the lower levels, suggesting later additions to the upper floors including a spiral staircase shell.

The core of these remains likely dates to the 13th century, with architectural features remarkably similar to those found at nearby Ballyderown keep, particularly the window openings which have been dated to between 1190 and 1220. The northeast corner contains intriguing remnants including an arched opening leading to a small vaulted chamber, complete with a garderobe chute on its external face; a medieval toilet facility that speaks to the castle’s former sophistication. Various lean-to farm buildings have been constructed against the ancient walls over the centuries, including a former milking parlour against the western wall and a gabled cottage parallel to the northern wall that appears on maps from 1842.

Mogeely Castle witnessed some of Ireland’s most turbulent history. First mentioned in 1404 when the Earl of Desmond acquired it from the Knight of Kerry, it became the residence of Thomás, Earl of Desmond before being reduced by Queen Elizabeth’s forces during the Desmond Rebellion. The castle later formed part of Walter Raleigh’s Munster Plantation holdings and was besieged during the 1598-99 uprising, holding out for four months. From 1610 to 1628 it served as the official residence of Sir William St Leger, Lord President of Munster, before falling to the Earl of Castlehaven in 1645 after an artillery bombardment. By 1750, it was already being described as the ruins of a “very large and stately building”, its days of grandeur long past but its stones still bearing witness to centuries of Irish history.