The millstone research carried out at the oppidum of Bibracte has recently been bolstered by finds deriving from preventive archaeology carried out at the Roman city of Autun. A new phase of this research has focused on the quern and millstone quarries supplying the two centres. Among the quarries is the vast vaugnerite outcrop of Bois de Joux at Saint-Andeux (Côte-d’Or). Field surveys identified two sectors producing mostly rotary querns dating to the Late Iron Age and Antiquity. Examining the roughouts renders it possible to reconstruct the operational sequence of their manufacture while the study of the quarries offers data to distinguish the Late Iron Age from the Roman quarries and identify their sequences of production.