The classification itself is curious: a designed landscape feature is not a ruin, not a monument, not a natural formation, but something deliberately shaped by human intent, a conscious intervention in the land, most often associated with the ornamental grounds of an estate or a planned agricultural setting.

Without further detail in the available material, the feature resists easy description. Pollnahallia is a place-name with Irish roots, and the area sits within a part of Connacht where landed estates once reorganised the landscape to reflect the tastes and ambitions of their owners. Designed landscape features could range from ornamental lakes and woodland walks to sunken fences, walled gardens, or carefully positioned tree lines meant to frame a view or screen a working yard. That something of this kind was noted here suggests that whoever surveyed the area found traces of that deliberate hand, even if what remains is subtle or partial.