What remains is roughly semicircular, running from south-west through north to north-east, and even in its truncated state the site preserves a surprisingly complex arrangement of banks, ditches, and berms across level pasture.

A ringfort, or rath, was typically a circular enclosed farmstead of the early medieval period, roughly 500 to 1000 AD, defined by one or more earthen banks and ditches intended to protect a household and its livestock. The Cooleagh example is multivallate, meaning it was defended by several concentric lines rather than a single circuit. The surviving half reveals an inner bank roughly 5.5 metres wide and over a metre high on the outside, followed by a flat-bottomed fosse, which is the technical term for a ditch, nearly 7.5 metres wide and just over a metre deep. Beyond that lies a berm, a level shelf of ground between two defensive lines, which widens noticeably toward the north-west and is flanked there by an additional low bank on its inner edge. An outer fosse and a further bank, possibly a later field boundary, complete the sequence. The interior of the enclosure sits in a slight concavity and is now densely overgrown. About 40 metres to the south-east stands a separate multivallate ringfort, making this a site within a small cluster of related enclosures, a pattern not uncommon in the Irish midlands and south, where prosperous farming settlements sometimes developed in close proximity over successive generations.