This is a ditch barrow, a type of prehistoric funerary monument defined not by a raised mound but by a circular ditch cut into the ground, often enclosing a central area where the dead were once interred or commemorated. At Ballynagrana, the defining feature is a scarp, a short, sloping edge of earth, running in a rough sub-circle roughly 5.2 metres in diameter, with a width of between two and two and a half metres and a height of only about thirty centimetres. At the northeast, that scarp dips slightly, and the shallow interior holds a depression no more than ten centimetres deep at its lowest. It is an easy thing to walk past without recognising it for what it is.

The monument was identified not by excavation or ground survey alone, but from above, appearing as a ring-ditch on an aerial photograph. Aerial photography has been one of the more quietly transformative tools in Irish field archaeology, revealing cropmarks and soilmarks that are entirely invisible from ground level, particularly in low-lying or waterlogged terrain. The wet, gently undulating character of this part of Tipperary, shaped by long-term natural water activity, has both preserved and obscured the site. The exterior of the barrow is saturated, and heavily poached by cattle on the northeast to southeast arc. A low bank running roughly east-northeast to west-southwest, slightly to the north-northwest, may represent an old field boundary or the upcast from a drainage channel, though its exact origin remains uncertain. What gives the site its wider significance is its context: a ring-barrow lies around fifty-eight metres to the west, and a further cluster of two ring-barrows and another ditch barrow sits between sixty-nine and seventy-seven metres to the east, suggesting that this particular stretch of ground was used, repeatedly and deliberately, as a place of burial or ritual during prehistory.