Built in 1838, it takes the form of an E-plan, meaning the floor plan resembles the letter E, with projecting wings and re-entrant corners that give the building an almost theatrical complexity. The entrance front bristles with fluted octagonal turrets, a canted oriel window, stepped corner buttresses, and bartizan features, small corbelled corner projections associated with medieval fortifications, here deployed in a purely decorative spirit. The garden elevation is seven bays wide and rises through triple-height canted bay windows with rendered openwork balconies. A chapel at the rear adds pinnacles, a cross finial, and crenellations to the composition. The whole surface is treated with moulded hood-mouldings, quatrefoil motifs, and decorative render bands, so that ornament accumulates on every face of the building simultaneously.

The architect was George Papworth, and Kilcornan is the largest of his country houses to survive. His client was Sir Thomas Redington, whose family left a considerable mark on this part of Galway. The Redingtons designed and developed the village of Kilcornan itself, laying it out around a walled green with a cenotaph to Thomas Redington at its centre. The site has a longer history still: before the 1838 house, the land was occupied by a sixteenth-century castle belonging to Ulick de Burgo, one of the powerful Connacht Burkes whose influence across the region stretched from the medieval period well into the early modern era. The present house, for all its Gothic ornament, sits on ground with considerably older associations. Around 1970 an additional storey with a flat roof was added to the main block, a pragmatic intervention that sits visibly above Papworth's original roofline without quite erasing it. The house now operates as a training centre for people with learning disabilities, and the extensive mature grounds remain part of the setting.