Most raths, the circular or roughly oval earthwork enclosures built across Ireland from the early medieval period onwards as farmsteads or defended homesteads, conform to a fairly consistent roundness. The example at Rathwilladoon in County Galway is a notable exception: it is distinctly D-shaped, with one straight side running along the south-west, giving the whole structure an angular quality that departs from the usual form.

The enclosure measures roughly 41 metres north to south and 38 metres east to west, making it a reasonably substantial example of its type, though time has not been kind to it. The defining bank of earth and stone has largely collapsed, and across much of its circuit, from the north-west around through east to south, it is further obscured by overgrowth. On the remaining sections, where vegetation has not entirely taken over, the boundary survives as a scarp, a low abrupt slope in the ground rather than an upstanding bank, which is often what survives when earthworks have been left untended for generations. The rath sits in level grassland, a setting that at least keeps the general outline legible if you know what you are looking for.