The ringfort at Laggoo sits on a hillock amid undulating farmland, its oval outline measuring roughly 38.5 metres east to west and 30 metres north to south. What survives is defined mainly by a steep scarp, the eroded remnant of what would originally have been a bank or earthen rampart encircling a domestic enclosure. The interior still sits 3.5 metres above the surrounding field level, which gives a sense of how substantial the original earthworks once were, even as the detail has worn away.

Ringforts, known in Irish as raths when they are earthen rather than stone-built, were the most common form of enclosed farmstead in early medieval Ireland, typically dating from roughly the sixth to the tenth centuries, though some were built and used outside that range. They functioned as defended homesteads for farming families, with the enclosing bank and ditch providing protection for people and livestock. The example at Laggoo is a modest one, and time has not been especially kind to it. A field boundary has been laid directly over the southern portion of the monument, which is a common enough fate for low-lying earthworks in agricultural land, where each generation of farmers works around, and sometimes through, what earlier generations left behind.