One is a circular hut site, sitting at the centre of the enclosure's interior; the other is a rectangular structure, visible in the southern sector, its right-angled plan suggesting a different tradition of construction entirely.

Hillforts are among the more debated monument types in Irish archaeology, their dates and functions ranging across the prehistoric and early medieval periods depending on the site. What makes Earlspark quietly interesting is the layering implied by these two structures. Circular hut forms are generally associated with prehistoric and early medieval settlement in Ireland, while rectangular plans tend to appear later in the archaeological sequence, though neither rule is without exception. The fact that both forms are present within the same enclosure raises the possibility that this was not a site occupied once and abandoned, but a place returned to, adapted, or reinterpreted over a long span of time. The rectangular structure is described only as a possible house site, meaning its identification remains tentative, read from surface traces rather than confirmed through excavation.