An Lios Buí Mór is a rath, a type of ringfort built in early medieval Ireland as an enclosed farmstead, typically for a single family and their livestock. The enclosure here is nearly circular, measuring roughly 31 metres east to west and just under 30 metres north to south, defined by an earthen bank that still stands around two metres high in places. That the name survives, an Irish placename meaning something close to "the big yellow fort" or "the big yellow enclosure", suggests the site remained a landmark in local memory long after anyone last farmed inside it.

What makes the construction here worth pausing over is the way the builders worked with, rather than against, the slope. The site occupies a north-west-facing hillside, and the interior has been deliberately cut back into the ground on the south-east side while the material was built up on the north-west to create a roughly level platform within the bank. This kind of terracing is fairly common in ringfort construction, but it is rarely so legible from a description alone. There are gaps in the bank to the south-east, south, and north-west, and a possible original entrance to the east-north-east, about two metres wide, which would have been the functional threshold of the enclosed space. A laneway still runs along the western side of the bank, a quiet sign that the landscape has continued to organise itself around this structure for a very long time. Inside the enclosure, the faint remains of cultivation ridges run on a north-west to south-east axis, suggesting the interior was worked as agricultural ground at some point after the fort's primary use had ended, or perhaps alongside it.

The site sits in pasture today, which tends to be the best condition for earthworks of this kind, as ploughing is the main threat to earthen monuments. The bank is visible as a continuous low rise around most of the circuit, and the terracing effect in the interior is apparent on the ground even if it takes a moment to read. The laneway to the west offers a natural line of approach.