The site, known locally as the Caher, a name derived from the Irish word for a stone fort, was recorded in October 1983 as a circular enclosure roughly 35 metres in diameter, sitting on a north-east-facing slope of gently rising ground. By 1988, it had been levelled entirely.

When surveyors visited in 1983, the fort was still legible in the landscape. A bank of earth and stone curved around the enclosure from the north-east, through the south, and back to the north-west, while on the remaining arc a natural scarp served as the boundary. Inside, two dividing banks subdivided the interior space, a feature that would have separated different functional areas within what was once likely a farmstead of the early medieval period, roughly between the fifth and twelfth centuries. A corbelled stone structure, the type sometimes called a clochan or beehive cell, may also have been associated with the site. Roughly 250 metres to the south-east, a separate ringfort survives, suggesting this corner of North Galway once held a loose clustering of such enclosed settlements, each probably the home of a single farming family and their livestock.

The Luimnagh ringfort is a reminder of how much of the early medieval countryside existed intact into living memory, only to disappear through agricultural improvement. No earthwork remains to visit today.