Beneath that variation lies a low, roughly circular mound of earth and stone, measuring about eight metres east to west and seven metres north to south, and rising to no more than around 0.7 metres at its highest point. There is no surrounding ditch, or fosse, which is notable because many earthen burial mounds from prehistoric Ireland are defined precisely by the hollow left when material was scraped up to form the mound itself. Its absence here is one of several reasons why the feature resists easy classification.

A mound barrow is, in general terms, a raised earthen or stone monument constructed over a burial or as a marker in the landscape, and examples in Ireland range from the Neolithic through to the early medieval period. What makes the Gortmore example unusual is how tentative its identification remains. It was recognised not through excavation or obvious surface archaeology but through the difference in vegetation colour that set it apart from the rest of the field, a quiet visual signal that something beneath the soil is altering how the ground behaves. The Dungolman River runs approximately 320 metres to the east, and another possible mound barrow has been noted around 120 metres to the north-east, which raises the possibility, though no more than that, of a modest cluster of features in this part of the townland. The antiquity of the Gortmore mound has not been confirmed, and without excavation or further survey the question of whether it is a prehistoric monument or a much later, entirely natural or agricultural feature remains genuinely open.