The manor first appears in records when Sir Simon Cusack granted it to his son John in 1380, though the property changed hands several times before settling with the Wellesley family in the early fifteenth century through the marriage of an heiress to Sir Richard de Wellesley, who had served as sheriff of Kildare. The Wellesleys would maintain ownership for the next three hundred years, converting to Protestantism after 1640 and steadily expanding their holdings throughout County Meath.

By the mid-seventeenth century, the Civil Survey recorded that Valerian Wellesley owned 380 acres at Dangan, complete with a castle, mill, thatched houses and a chapel, plus nearly 600 additional acres elsewhere in the parish. The estate’s most famous connection came through Garret Wellesley, who died childless in 1728 and left the property to his cousin Richard Colley of Castlecarbury, on the condition that he adopt the Wellesley surname. Richard’s grandson, Arthur, would reportedly be born at Dangan on 1 May 1769 before going on to defeat Napoleon at Waterloo and becoming the first Duke of Wellington. Despite this illustrious connection, the family’s fortunes declined; Arthur’s father, the musically gifted Earl of Mornington, mortgaged the estate heavily to fund his expensive lifestyle.

Today’s ruins primarily consist of an eighteenth-century mansion built atop the original tower house site, likely constructed by Richard Colley Wellesley as part of his improvements to the estate, which included draining the surrounding land. A 1699 drawing by Francis Place shows the medieval tower house still standing three storeys high, and some of its fabric may survive in the thick walls and base batter of the current ruin’s east wing. After the Wellesleys lost the property to their debts at the century’s end, it passed to Thomas Burrowes, whose tenants allowed the castle to burn in 1809; it was never restored, leaving the atmospheric ruins that stand today as a monument to both the rise and fall of one of Ireland’s most prominent Anglo-Irish families.