Built between 1631 and 1632, shortly after the completion of the walled garden itself, the structure showcases the architectural ambitions of the early 17th century. The gateway consists of an elaborate archway flanked by two rectangular towers, each rising three storeys high, with a connecting passage at first floor level creating a unified defensive structure.

The Riding House gateway represents a fascinating layer in Lismore Castle’s long history, demonstrating how the castle complex evolved beyond its medieval core. Its construction in the 1630s came during a period of relative stability in Ireland, when aristocratic estates were investing in both defensive features and architectural grandeur. The twin towers and connecting passage would have served multiple purposes; providing accommodation for guards or staff, controlling access to the castle grounds, and making a bold architectural statement to visitors approaching from the south.

Archaeological surveys conducted by Bradley, Halpin and King in 1989 have helped document this structure as part of the broader castle complex, which includes the main castle building and its extensive walled garden. The gateway’s position, attached to the southern side of the castle and forming part of the garden’s perimeter, reveals careful planning in the estate’s layout, where defensive needs, practical access and aesthetic considerations all played important roles in shaping this remarkable piece of Irish heritage.