Built by the O'Madden clan, who held these lands as vassals of the O'Kelly lords, the castle served as both a defensive stronghold and a family residence during turbulent times in Irish history. The structure rises four storeys high, with thick limestone walls that have weathered centuries of Atlantic storms and political upheaval.

The castle's design reflects the practical needs of medieval Irish nobility; its narrow windows, murder holes, and machicolations speak to an era when comfort took second place to security. Inside, visitors can still see the remnants of the great hall, where the O'Maddens would have entertained guests and conducted clan business, whilst the upper floors contained private chambers for the family. A particularly interesting feature is the castle's intact spiral staircase, which winds clockwise to give right-handed defenders an advantage against ascending attackers.

Following the Cromwellian conquest in the 1650s, the O'Maddens lost their ancestral home, and Rathgorgin passed through various hands before eventually falling into disuse. Today, the castle remains in private ownership but stands as an evocative reminder of Gaelic Ireland's tower house tradition. Its isolated position in the Galway countryside, surrounded by grazing cattle and stone walls, offers visitors a glimpse into a way of life that dominated this region for centuries before the plantations and penal laws changed Ireland's social landscape forever.