It is also one of the most concentrated areas of prehistoric monument in the country, and somewhere within that grey expanse at Gleninsheen sits a wedge tomb, the type of megalithic structure most commonly found in the west of Ireland and dating broadly to the later Neolithic and early Bronze Age periods, roughly three to five thousand years ago.

Wedge tombs take their name from their shape in plan and in profile: the burial gallery is wider and taller at one end, typically the west-facing entrance, and tapers toward the other. They are the most numerous of Ireland's megalithic tomb types, and the Burren holds a remarkable concentration of them. The Gleninsheen tomb sits in a landscape already associated with one of the most celebrated finds in Irish prehistory, the Gleninsheen Gorget, a gold collar dating to the late Bronze Age, discovered in the area in 1932. The tomb itself predates that object by a considerable margin, though both speak to the sustained human significance of this particular valley over millennia. The principal scholarly treatment of this monument appears in the 1961 survey by Ruaidhrí de Valera and Seán Ó Nualláin, which catalogued the megalithic tombs of Clare in systematic detail and remains a foundational reference for the county's prehistoric archaeology.

The Burren rewards slow movement. The limestone pavement, known as karst, is deeply fissured with cracks called grykes, and progress across open ground requires care. The tomb at Gleninsheen is best approached with some awareness of the terrain underfoot and the way that monuments here can appear almost continuous with the rock around them, the orthostats and capstones blending into the general grey surface until you are almost on top of them.