It is easy to miss, and easier still to misread. The enclosure measures roughly twenty metres east to west and ten metres north to south, its bank running from north around to the east and southwest, and again from west to northwest. Internally the ground has been deliberately built up on the downhill, eastern side to create a level platform, which is itself the detail that makes the site interesting: that kind of earthmoving effort suggests the place was meant to be used, not merely bounded.

A booley hut is a seasonal shelter associated with the old Irish practice of booleying, in which people, usually young women and men, would move cattle to summer pastures on higher ground and live there temporarily while the animals grazed. The word comes from the Irish buaile, meaning a milking place or summer pasture. Structures associated with booleying tend to be modest and impermanent, built for a few months of use rather than for longevity, which is part of why so few survive in recognisable form. At Coolnagoppoge, within the larger enclosure, there is a raised sub-rectangular area of approximately eight metres by two metres that may represent the platform on which such a hut once stood. The outer enclosure itself may have served as a sheepfold rather than, or perhaps as well as, a booley enclosure, and the two uses are not necessarily incompatible across different periods of occupation.