The earthworks here form an oval enclosure, roughly 35 metres north to south and 24 metres east to west, and they belong to a class of monument that was once extraordinarily common across Ireland. A rath, or ringfort, is an enclosed farmstead of the early medieval period, typically dating from around the fifth to the twelfth century, defined by one or more banks and ditches and used as a defended homestead for a farming family and their livestock.

What survives at Rathgallen is a coherent if weathered structure. The enclosing earthen bank is best preserved on the east-southeast side, where it stands around 2.2 metres high on its outer face and reaches more than five metres in width; on the west-southwest it is considerably lower, reduced in places to little more than a scarp. A causewayed entrance, a deliberate gap left in the bank with a raised causeway crossing the ditch, sits at the west-northwest at around 1.5 metres wide, with a second break of approximately 2 metres in the eastern bank, though this one is largely obscured by undergrowth. The outer fosse, a broad U-shaped ditch running around the exterior of the bank, is still visible at around 3.5 metres wide and 0.6 metres deep, though the plough has bitten into its outer edges over the years. Inside, the ground is roughly level, covered in nettles and edged with briars, the kind of undisturbed tangle that often marks out a protected monument in otherwise cultivated land. A second ringfort lies roughly 285 metres to the northwest and is visible from this one, a reminder that these enclosures were not isolated curiosities but part of a settled, organised early medieval landscape.