In a field in Hobartstown, County Kildare, there are two ancient enclosures that most people walking past would have no idea existed. They are invisible at ground level, detectable only from the air, where the buried remains of their ditches alter the growth rate of crops above them, producing faint but legible outlines known as cropmarks. One enclosure is circular and incomplete, its arc interrupted or perhaps never finished; the other, sitting immediately to its north-east, is large and rectilinear. Together they form a pairing that raises more questions than it answers.

Both features are defined by a fosse, the term used for a ditch dug as a boundary or defensive measure, often accompanying an earthen bank. The circular form is common across Ireland and typically associated with the early medieval period, when ringforts served as enclosed farmsteads for individual households or small communities. The rectilinear enclosure beside it is a less common shape in the Irish archaeological landscape, and its proximity to the circular feature suggests the two may have had some functional or chronological relationship, though without excavation that remains speculation. The cropmarks were captured in aerial photograph GB96.GE.31, which remains the primary evidence for what lies beneath the soil here.