The demesne, which surrounds Westport House and was shaped in the eighteenth century into a designed landscape, conceals traces of earlier occupation that predate the formal gardens, the ornamental lake, and the pleasure grounds laid out for the Browne family. A settlement cluster is precisely what the name suggests: the remains, sometimes visible as earthworks, sometimes only detectable through survey, of a group of structures that once formed a community, most likely from the medieval or early modern period.

Westport Demesne has a layered past that tends to be overshadowed by the Georgian house at its centre. The Browne family, later the Marquesses of Sligo, developed the estate from the late seventeenth century onwards, and the creation of that designed landscape almost certainly disturbed, absorbed, or obscured whatever settlement existed on the land before them. It is not unusual for Irish demesnes to contain such buried or semi-visible traces; the clearance of earlier habitation to make way for parkland was a common feature of estate-building across the country. That a formal record of this particular cluster exists at all is a reminder that the archaeology beneath ornamental grounds is rarely as tidy as the grounds themselves.