The castle occupies a strategic position with two small tidal inlets to the east and west-northwest that serve as natural landing points, whilst gentle pastureland rises to the south. Local legend suggests it was built three years after nearby Seanmuckinish castle, earning it the ‘nua’ (new) designation, though architectural evidence points to 15th century construction. The castle appears on historic Ordnance Survey maps from 1842 and 1915, marked as already in ruins, with records confirming its ruinous state by 1837.

The ownership history of Muckinish Castle reads like a who’s who of Clare’s medieval and early modern nobility. For most of the 16th century, the O’Loughlins held the fortress, but the 17th century saw it change hands multiple times between prominent local families. The Neylons gained possession, including Daniel Neylon, first husband of the formidable Máire Rua. After Daniel’s death, the castle passed to their son William, and later came under the control of Máire Rua and her third husband, John Cooper. By 1659, John Tully held tenancy, likely leasing from either Cooper or the Blakes, who were recorded as farming the surrounding lands in 1705.

What remains today is a substantial four-storey tower house, with the north wall stretching 8.5 metres and reaching an impressive height of 17.5 metres. Built from roughly dressed limestone rubble laid in irregular courses, the structure retains several refined architectural features including vaulted ceilings over the ground and second floors, five defensive arrow loops with splayed embrasures, and two elegant double-light ogee-headed windows in what would have been the solar. A garderobe shaft runs the full height through the western wall, whilst a curious lintelled opening on the second floor leads to a chamber that may have served as an oubliette or prison cell. Large rubble fragments scattered south of the castle, including portions of a chimney flue and stairwell, suggest parts of the structure may have been deliberately demolished with gunpowder. The castle stands within a bawn enclosure, with a small rectangular building positioned at its southwest corner.