The Ordnance Survey's 1838 six-inch map shows it plainly enough: a circular embanked enclosure, planted with trees, sitting on elevated ground in Co. Mayo with open views in every direction. Ninety years later, the revised edition records nothing. The enclosure had been levelled, and whatever had made it legible to nineteenth-century cartographers was gone.

What survives is legible only to patient eyes. A rath, in the Irish tradition, was a roughly circular earthen enclosure, typically defined by one or more raised banks and an outer ditch, used as a farmstead or defended homestead during the early medieval period. At Robeenard, the interior platform still reads faintly across the pasture as a slightly raised flat area measuring roughly 27.5 metres north to south and 34 metres east to west, its edge marked by a low, levelled scarp rather than anything you might call a bank. Beyond that, barely discernible undulations in the grass hint at an encircling fosse, the technical term for the external ditch that would once have defined and defended the structure, here estimated at around 2.5 metres wide. An outer bank, some 4 to 5 metres across, can also just about be traced. At the western and northern edges, a scatter of surviving trees follows what was once the perimeter, the last above-ground remnant of the planted enclosure recorded nearly two centuries ago.

This is a site that rewards a certain kind of attention. The surrounding pasture is level and open, which means the slight rises and dips that encode the rath's former shape are easier to read in low, raking light, particularly in the early morning or late afternoon when shadows lengthen across the grass. There is no dramatic earthwork to orient you; what you are looking for is the landscape's hesitation, the place where level ground is almost, but not quite, flat.