The enclosing wall is irregular, poorly constructed in places, and ranges from little more than half a metre to just over a metre in height. But look more carefully at the south-eastern sector and the picture becomes more complicated. A substantial plinth, up to 1.5 metres high and nearly 2.75 metres wide, sits at the base of the outer wall face, revetted with large upright stones and topped with drystone walling. This feature, and a corresponding mound of collapsed stone along the western and northern sides, may well represent the remains of an earlier, more substantial cashel wall, with the current enclosure built as a later addition around or against it.

A cashel is essentially a ringfort built from stone rather than earth and timber, a form of enclosed farmstead typical of early medieval Ireland. This particular example sits within a landscape documented by J. Cuppage in the 1986 Dingle Peninsula archaeological survey, which catalogued the dense concentration of prehistoric and early medieval remains across the Corca Dhuibhne peninsula. The cashel at Ulacha is modest in scale, roughly 13 metres across north to south and 16 metres east to west, but it carries a few details worth pausing over. A four-metre-wide gap in the south-eastern wall was once the entrance, formerly giving access to a small triangular field that still adjoins the site on that side, the gap now blocked. More intriguing is a possible souterrain, an underground passage or chamber often associated with ringforts and used variously for storage or refuge, which appears to run beneath the wall at the north-western side. It is no longer accessible, but a partly stone-lined hollow at the base of the inner wall face marks where it begins.