Derryquin Castle was an 18th-century stone-built country house, now demolished, in the Parknasilla estate in Sneem, County Kerry in the Republic of Ireland. It stood on the Ring of Kerry route some 40 km (25 miles) south-west of Killarney. Designed by local architect James Franklin Fuller, the house comprised a three storey main block with a four storey octagonal tower rising through the centre and a two storey, partly curved wing. The building was equipped with battlements and machicolations.