What gives it away is the geometry: three upright slabs forming a wedge-shaped chamber just 2.5 metres long, narrowing from 1.5 metres at the southwest end to 1.2 metres at the northeast, and covered by a single roofstone. On top of that capstone, someone has piled a rough stack of field stones, probably cleared from the surrounding land over the centuries. The whole structure sits within a low earthen mound, and the open end faces southwest, which is characteristic of this type of monument.

Wedge tombs are the most numerous of Ireland's megalithic tomb types, built during the late Neolithic and into the early Bronze Age, broadly between around 4,000 and 2,500 years before the common era. The form is consistent: a chamber that tapers and decreases in height from front to back, typically oriented with the wider, higher entrance facing roughly west or southwest. The Doorus example is a notably simple specimen of the type. It was recorded by Ruaidhrí de Valera and Seán Ó Nualláin in their systematic survey of megalithic tombs across Ireland, published in 1972, which remains a foundational reference for this category of monument. Doorus Demesne, the wider landscape in which it sits, occupies a peninsula between Kinvarra Bay and Galway Bay, a part of south Galway where prehistoric remains are not uncommon given the long history of human settlement along these limestone shores.