The icehouse to the east of Kilshannig House in County Cork is a compact example of this once-common feature of Georgian and Victorian estates, though its octagonal form sets it apart from the more usual barrel-vaulted underground chambers found elsewhere. Most icehouses were built to be invisible, dug into hillsides or earthen banks to exploit natural insulation, but here the above-ground structure was given some architectural attention, with brick surrounds framing both the west-facing door and the south-west-facing window.

The building is small, just over two metres in diameter, and the functional logic of its layout is still legible despite the roofless condition and the collapse of the eastern side. Beneath the floor lies a chamber roughly two metres deep where ice was packed and stored, insulated from the air above. A chute in the north wall would have allowed ice to be fed down into the chamber, likely from a cart or barrow brought alongside. This kind of arrangement was standard on estates that could afford it: winter ice was cut from ponds or slow-moving water, packed with straw or sawdust to slow melting, and drawn on through the warmer months to cool larders, preserve game, and chill drinks for the household at Kilshannig House nearby.