In May 2001, the monitoring of topsoil-stripping for the Hollybrook to Wicklow Bord Gáis Éireann pipeline revealed something considerably older beneath a field in the townland of Tiglin, Co. Wicklow: a cluster of pits, post-holes, and fire-cracked stone that pointed to a fulacht fia, the Irish term for a prehistoric burnt mound site. These are among the most common archaeological monuments in Ireland, generally understood to be outdoor cooking or heating sites where stones were fired and dropped into water-filled troughs, though their precise functions remain debated. The Tiglin example was sitting quietly on the crest of a gentle north-to-south slope, with the coastline to the east and a larger hill to the west, in a field that had been under cultivation long enough to have shaved away some of the archaeology before anyone thought to look.

Excavation, carried out over May and June 2001, revealed around ten pits and several post-holes arranged in and around the edges of a large pre-existing depression. That depression was the puzzle at the centre of the site: a broad, V-shaped cut measuring roughly 6.6 metres east to west and 7.9 metres north to south, reaching a maximum depth of 1.17 metres, and filled with stony layers and silty clays containing traces of charcoal. Excavators considered whether this hollow might originally have been a peri-glacial feature, a remnant of the last Ice Age rather than of human digging, though the charcoal flecking in its fills complicates a tidy conclusion. Whatever its origins, prehistoric people appear to have made practical use of it, possibly exploiting moisture retained in the backfill for water accumulation. The pits cut into its upper fills and surrounding subsoil were mostly wide and shallow, but one to the south-east was more complex, with eight distinct layers of fire-cracked stone, charcoal, and redeposited material, along with a single post-hole at its base. Over these pits lay two spreads of heat-shattered stone, the classic debris of fulacht fia activity. A crude flint scraper turned up during initial clearance, and charcoal analysis identified hazel as the dominant fuel wood, with oak also present.