Excavations carried out between 1970 and 1972 found no burials whatsoever within its roughly subrectangular boundary, measuring about 21 metres east to west and 20 metres north to south. What they did find was rather more unexpected: a copper-working furnace just west of the doorway of St. Brigid's church, evidence of iron-working immediately to the church's north, and further metalworking remains outside the enclosure to the west. The paving inside the wall appears to have been laid for the making of stations or rounds, the traditional practice of walking a prescribed devotional circuit at a sacred site, suggesting a place of active religious use rather than burial.

The enclosure surrounding St. Brigid's church has a long and layered history. Before the 1970 to 1972 excavations, its western, northern, and eastern sides were defined by an earthen bank with some stone; the drystone wall uncovered beneath later construction proved to be the last in a sequence of enclosing features, each repaired or rebuilt over the centuries. A deep V-shaped fosse, a type of ditch, ran along the northern sector, and a broader, shallower fosse lay to the east; both are thought to belong to an early phase of activity on the island. Radiocarbon dating of a hazel sample from the fill of the northern fosse produced a date range of approximately AD 992 to 1150, and two bone comb fragments recovered from the same fill have been dated to around AD 1050 to 1125. The mortared stone wall that now forms the southern boundary of the enclosure was not an original feature at all; it was built early in the thirteenth century as part of the construction of St. Mary's church, located about 30 metres to the south, and was simply incorporated into the enclosure's boundary at that point. The round-headed entrance midway along the southern wall, with its simple interior moulding, dates to this period of more formal stone construction.