Enclosures of this kind are among the most common and least understood monument types in Ireland. The word covers a broad range of structures: from the substantial stone-walled ringforts that once served as defended farmsteads in the early medieval period, to more ephemeral earthwork boundaries whose age and purpose remain genuinely unclear. That ambiguity is part of what makes them worth paying attention to. A line drawn around a piece of ground, in earth or stone, always raises the question of what someone once thought worth enclosing.