Excavation in the south-western quadrant of the enclosure turned up evidence for several wooden structures, some circular in plan and some rectangular, the kind of traces that survive not as walls but as post-holes, beam slots, and soil discolouration.

Ecclesiastical enclosures of this type, roughly circular or oval boundaries that demarcated sacred ground in early medieval Ireland, were often home to a mixture of religious and domestic activity. The buildings inside could serve as oratories, sleeping cells, workshops, or stores, and it was common for communities to use timber construction even when stone was readily available locally. At Caherlehillan, the presence of both circular and rectangular plans is notable: circular wooden structures are among the earliest forms of building in early Christian Ireland, while the rectangular plan gradually became more associated with ecclesiastical use as the period progressed. The excavations, carried out by John Sheehan across a series of seasons documented from 1994 through to 2006, brought this variety of evidence to light incrementally, with each season adding to the picture of how the south-western part of the enclosure had been used and reused over time.