The only evidence of it visible from above is a small opening, measuring roughly 40 by 45 centimetres, set into the north-western quadrant of the earthwork's interior. That aperture is the beginning of a souterrain, an underground stone-lined passage or chamber of a type built across early medieval Ireland, typically associated with raths and ringforts. They were used variously for storage, refuge, or ventilation, and they tend to attract speculation in proportion to how little of them can actually be seen.

The rath itself provides the context. A rath, sometimes called a ringfort, is a roughly circular enclosure defined by an earthen bank and ditch, and was the standard form of farmstead in early medieval Ireland, broadly from the fifth to the twelfth century. The souterrain at Cloghera More sits within the raised interior of one such enclosure, where the ground level has been built up or preserved above the surrounding terrain. Beyond the dimensions of its entrance and the general orientation of the passage, nothing more about its layout or condition has been formally established. It is recorded as inaccessible, meaning the passage itself cannot be entered or examined directly.