When geophysical surveys and test trenches were carried out ahead of the construction of the M3, a patch of gently undulating, east-facing ground near Phoenixtown was found to contain the compressed remains of a whole agricultural complex: a road running east to west, five corn-drying kilns, a threshing floor, a well, a water-hole, and the corner of a house. Excavations across an area roughly 100 metres by 45 metres, carried out in 2006 and 2007, produced a picture of intensive grain processing that had been quietly buried under plough furrows for the better part of seven centuries.

One of those kilns, a narrow oval channel cut through burnt clay and measuring roughly 2.66 metres by one metre, sat about six metres north of the threshing floor. A corn-drying kiln was typically a low, fire-heated structure used to dry grain before milling or storage, particularly important in the damp Irish climate where grain harvested still wet could quickly spoil. Only the base of this example survived, filled with layers of sandy silt and, in the upper layer, concentrated charcoal. Carbonised remains recovered from the kiln included oats, wheat, barley, and peas. The ceramic evidence places all five kilns and the associated features in the period from the late twelfth to the fourteenth century. The place-name itself offers a small puzzle: Phoenixtown is an anglicisation of Finnogestown, which in turn comes from the Irish Baile na bhfionnóg, meaning roughly "town of the grey crow." The settlement first appears in the documentary record in 1324, as Fenokston, in an inquisition into the manor of Martry. Among the free tenants listed are David Beg, Adam Beg, and Richard Lewati, holding around 300 acres, and these families are likely the people who worked the kilns and threshing floors now partially uncovered beneath the motorway corridor. The manor itself had a complicated history: granted by Hugh de Lacy to Jocelin de Angulo after the Anglo-Norman settlement of Meath in 1172, it had passed through several hands by 1318, when its holder Walter de Say forfeited it to the Crown, probably for actions taken during the Bruce campaign. By 1415 it had passed to the Darcy family, though the Beg name continued to appear in local documents throughout the fourteenth century.