Summerhill was a Norman-Irish estate belonging to the Lynch family, and was awarded to Dr Henry Jones, Bishop of Meath, by Oliver Cromwell. Jones then sold the estate in 1661 to Sir Hercules Langford. Sir Hercules's grandson, Hercules Rowley, built Summerhill House from 1731, possibly to the designs of Sir Edward Lovett Pearce (c1699-1733). At this time the Lynch family's original castle was abandoned as a ruinous folly. Hercules Rowley's son was the Rt Hon. Hercules Langford Rowley, a member of the Irish Privy Council, who succeeded in 1742. Hercules Langford Rowley commissioned Robert Adam to make a design for an extension to Summerhill House in 1765. This was composed of a quadrant link connecting two wings, and it was not executed.

A year later, in 1766, Hercules Langford Rowley's wife Elizabeth was created Viscountess Langford, a title which was inherited by their son, also Hercules Langford Rowley, 2nd Viscount. The 2nd Viscount died in 1796 without an heir, and the Summerhill estate passed to his sister Jane, who had married Clotworthy Taylor, Earl of Bective.

Summerhill House was burnt by the Irish Republican Army in 1921, and its gutted shell was eventually demolished in 1970.

See also: Langford House, Mary Street, Dublin, and Headfort House, County Meath.

Literature:
A.T. Bolton, The architecture of Robert and James Adam, 1922, Volume II, index pp. 29, 86; J. Lees-Milne, The age of Adam, 1947, p. 165; J. Harris, 'C.R. Cockerell's 'Icnographica Domestica' ', Architectural History 14, 1971, p. 26; D. King, The complete works of Robert & James Adam and unbuilt Adam, 2001, Volume II, p. 121

Frances Sands, 2013