It was excavated in the 1940s and yielded almost nothing in the way of answers, only small pockets of cremated bone tucked at intervals around the kerb, and no dating evidence whatsoever. The monument sits there still, classified, protected, and largely unresolved.

A ring-cairn is a prehistoric funerary structure in which a circular kerb of stones encloses a hollow or low interior, distinguishing it from a solid burial mound. This particular example on Knockfennell was excavated under the direction of Dr S. P. Ó Ríordáin, one of the leading figures in mid-twentieth-century Irish archaeology. He described it plainly as a small cairn on a hill-top and published his findings in 1954, noting that the results were inconclusive. O'Kelly, writing in 1944, had earlier classified it as a ring-barrow, a term sometimes used interchangeably but generally associated with earthen rather than stone construction. The 1978 re-examination by O'Kelly and O'Kelly settled on ring-cairn, and that classification has held. The monument has been subject to a preservation order since 1941, issued under the National Monuments Acts. What makes its setting particularly striking is the sheer density of prehistoric remains in the surrounding landscape: a stone circle lies roughly 220 metres to the south-south-east, Red Cellar cave sits 65 metres to the south-east, and the remnants of a field system, hut sites, and a cashel, a type of early stone-walled enclosure, are grouped to the south-west. Lough Gur, one of the most archaeologically significant lakes in Ireland, lies 235 metres to the south.

From the summit, on a clear day, the ring-cairn known as Dun Gair on the top of Knockmore is visible 780 metres to the south-south-east, similar in size and form to the Knockfennell monument. The Lough Gur area is well signposted from the main road between Bruff and Herbertstown, and the landscape around the lake is largely open and walkable. The summit of Knockfennell is not a managed visitor site, so the approach involves some reading of the terrain. Once at the top, the continuous stone kerb is the thing to look for; the hollow interior is subtle but unmistakable once you are standing beside it.