The land here has witnessed centuries of Irish history, from medieval castle warfare to the upheavals of the Cromwellian period and beyond.

The original stronghold on this site was Rinekirky Castle, a Desmond fortress that surrendered to English forces in 1569 during the tumultuous Desmond Rebellions. By 1583, it was held by the Knight of Glan, and various records from the late 16th century place it firmly in the barony of Kenry. The Fitzgerald family maintained control of the property through the early 17th century; the Civil Survey of 1654-56 records that Gerrott Oge fitz Gerald held the estate at Mullane, describing it as comprising "one good house, & six smale cottages" along with a valuable salmon weir on the Shannon.

The property changed hands in 1703 when it was sold to Phineas Bury, who subsequently granted it to T. Westropp of Ballysteen. Westropp left it to his second son Mountiford in 1744-45, and his descendants retained ownership well into the modern period. The current Mellon House, built by the Westropp family in 1780, represents a typical Georgian reinvention of an ancient Irish estate, transforming a site of medieval conflict into a gentleman's residence whilst maintaining its strategic position at this important river confluence.