It measures roughly four metres north to south and three metres east to west, rising only to about 0.8 metres at its highest point. There is no visible fosse, the surrounding ditch that typically accompanies a burial mound, which makes the monument harder to read at ground level. What it lacks in dramatic presence it more than compensates for in situation: the views from the summit extend in every direction, across Sligo Bay to the north and south towards the Ox Mountains.

This is a mound barrow, a form of prehistoric funerary monument in which the dead were interred beneath a constructed earthen or stone mound. The knoll on which it sits was clearly chosen with care. To the east, the profile of Knocknarae rises with Maeve's Cairn visible on its crown, one of the largest unexcavated cairns in Ireland and traditionally associated with the legendary queen Medb. That the builders of the Sheeanmore barrow could see Knocknarae from their own burial place, and presumably vice versa, is the kind of deliberate spatial relationship that prehistorians frequently note across the Irish landscape. The hill carries other traces of human use as well. Downslope to the west lies a children's burial ground, a cillín, the informal, unconsecrated burial sites used in later centuries for unbaptised infants and others excluded from churchyard burial. Field banks from a later agricultural system also cross the hillside, layering one era of activity over another.