The enclosure at Nicholastown is barely legible in the landscape now, a slight scarp rising only 0.27 metres above the surrounding ground, with an accompanying fosse, a shallow outer ditch, that betrays itself less by any depth or definition than by the fact that it sits wetter than the pasture around it. The ground holds water differently inside that ring, and that difference is sometimes the only way to read it.

The site sits atop a ridge that slopes away to the east and south, giving open views in those directions while the land rises to close things off northward and westward. It measures roughly 40 metres north to south and 38 metres east to west today, though it was apparently larger and more clearly defined in the nineteenth century. The first edition six-inch Ordnance Survey map of 1839 shows it as a small, roughly square field of approximately 48 metres by 48 metres, with trees both inside the boundary and around its edge. The later 25-inch OS map records a similar outline, slightly irregular in shape, widening a little toward the south end, and again with trees marked within it. Enclosures of this kind, broadly circular or sub-circular earthworks defined by a bank and ditch, are common across Ireland and are often associated with early medieval settlement, though many carry later folklore. Here, local tradition simply called it a fort, the word Irish communities have long applied to ancient circular earthworks, places set apart from ordinary ground by age, by shape, and by a certain unease about disturbing them.