What makes this particular enclosure interesting is not what you can see from the ground, which is very little, but what a researcher named F.T. Reilly found when he dug into it in 1935, and the quietly accidental way the investigation began. A local farmer had been digging in the fosse, the outer ditch that once defined the boundary of the enclosure, and turned up an iron pin. That small discovery prompted Reilly to carry out a formal excavation, cutting three long trenches across and through the site on behalf of the National Museum of Ireland.

The monument is a ringfort, or the heavily eroded remains of one. Ringforts, which are circular enclosures defined by earthen banks and ditches, were the most common form of rural settlement in early medieval Ireland, typically dating from roughly the fifth to the twelfth centuries. By the time Reilly arrived, the rampart at Shanaclogh East had been levelled and the fosse largely filled in, leaving only that low platform and a shallow depression to hint at the original form. His trenches told a more specific story. In the fosse, beneath a layer of stony clay, excavators found a continuous charcoal stratum containing animal bones, including those of red deer, a fragment of a rotary quern used for grinding grain, an iron pin, and a mass of iron. Inside the enclosure, an irregular line of stones was uncovered that may represent the foundation of a dwelling. A flint arrowhead and a bone marrow scraper were also recovered from the interior. The site does not appear on Ordnance Survey historic maps, and no evidence of earlier occupation was found beneath the cultural deposits. Oola Castle and a deserted medieval village lie within 380 metres to the north-east, suggesting this corner of the Limerick countryside was once considerably more populated than it appears today.

The enclosure sits in pasture immediately south-west of a road marking the townland boundary between Shanaclogh East and Oolahills East, about forty metres south of Shanaclogh House. It does not announce itself. Aerial photographs from 1968 and 1969, and orthophotographs from the 2000s, show the circular outline more clearly than anything visible at ground level. A further circular cropmark to the immediate south of the monument may represent post-1700 drainage works associated with the landscaping of Shanaclogh House rather than any earlier feature, so not everything visible from above is ancient. The site is on private farmland, and the low earthwork blends easily into the surrounding field.