Built in 1806 by George Plunkett and home of the Plunkett family until the mid 19th century when it became the property of Patrick Grehan. Described in the Crotty sale rental of 1851 as a 'superb mansion' repaired by Mr Crotty at a cost of upwards of £2,000. Grehan held the house, valued at £30, in fee, at the time of Griffith's Valuation. Samuel Richard Prosser lived in Mount Plunkett in the 1860s. The entrance gates are still in use but only walls remain of the house and outbuildings. Robert Adamson was apparently living at Mount Plunkett in the 1870s.