Rory MacNamara, son of Shane, son of Mahon, built this stronghold in the medieval period, establishing what would become a contested seat of power. By 1570, the castle had passed to Turlough O’Brien, younger brother of Conor, the third Earl of Thomond. Conor’s execution in Galway after 1581 didn’t end the family’s connection to Fomerla; his son Donagh inherited the earldom and, in 1585, transferred the castle to Roland Delahoyde, an arrangement renewed in 1613.

The turbulent 1640s saw Oliver Delahoyde lose possession of the castle, with John Carroll taking ownership. By 1659, the records show Cnarlse and Donagh Carthy as tenants, suggesting the property had shifted from residence to rental holding. The Moland survey of 1703 paints a melancholy picture: a castle fallen into disrepair, accompanied by the remnants of an old house, an orchard, and six small cabins.

Today, nature has largely reclaimed Fomerla Castle. The southwest wall stands as the most intact feature, stretching 2.5 metres northwest to southeast and rising 2.9 metres high, with walls 1.3 metres thick. Part of an embrasure remains visible at the northwest end. Four metres to the northeast, grass covers what remains of another wall running six metres in length, whilst collapsed masonry nearby shows traces of dressed stonework, including a window splay and stepped embrasure; architectural details that hint at the castle’s former sophistication.