Rathmweel sits on a low, narrow ridge running north to south in pasture near Newtown, with the north-eastern shores of Lough Conn lying roughly 400 metres to the west. From this modest elevation, the surrounding low-lying terrain opens up in every direction, which likely explains why people chose this ground in the first place.

A rath is a roughly circular enclosure defined by earthen banks and ditches, built during the early medieval period and typically associated with a farmstead or the residence of a person of some local standing. What sets Rathmweel apart from the more common single-banked example is its triple enclosure: three concentric banks separated by two intervening fosses, or ditches. The innermost bank, around 4.5 metres wide, still carries a thin capping of small stones in places and drops steeply into the first fosse. The middle bank is noticeably lower and more eroded than its neighbours. The outermost bank, also 4.5 metres wide and rising nearly two metres on its interior face, has been absorbed into a field boundary along its north-western to north-eastern arc, a common fate for earthworks in agricultural landscapes. The name Rathmweel appears on Ordnance Survey maps from both 1838 and 1930, suggesting it has long been a recognised local landmark. Where the original entrance once lay is now uncertain; gaps appear at the east-south-east and north-west but both are heavily obscured by vegetation. The enclosing banks are ringed with hazel, and the interior has become an impenetrable mass of brambles and thorn bushes. More striking still is the immediate neighbourhood: within 500 metres of Rathmweel there are at least four other raths and a church site, forming a concentration that points to sustained early medieval activity across this corridor of ground above Lough Conn.