The structure recorded in the townparks of Birr, County Offaly, was a tuck mill, a type of fulling mill used in the finishing of woollen cloth, where fabric was pounded with heavy wooden hammers driven by waterpower to thicken and mat the fibres. That such a specialised operation was established here points to a degree of textile activity in the town that might otherwise go unnoticed.

The mill appears on a 1691 plan of Birr town and is also identified as the "Little Mill" on a map of the same date made by Michael Richards. The two documents, discussed by Feehan and Rosse, place the mill firmly within the landscape of late seventeenth-century Birr, a period when the town was being actively developed and mapped in some detail. The Richards map in particular suggests a degree of cartographic ambition unusual for an Irish provincial town of that era, and the fact that this modest mill warranted its own label implies it was a recognised feature of the settlement rather than a peripheral curiosity.