[2] It was created on 4 August 1776 for Hugh Massy, who had previously represented County Limerick in the Irish House of Commons.

His great-grandson, the sixth Baron, sat in the House of Lords as an Irish representative peer from 1876 to 1915.

The house was demolished in 1941, but the Killakee estate, popularly known as Lord Massey's Wood, is now a much valued public amenity.

Another seat from the 1790s was Hermitage House in Castleconnell, County Limerick, until it was burnt in June 1920, being demolished in the 1970s.

His heir apparent is his son Luke John Somerset Massy (born 1984).