The BVSG dwelling at Longueil-Sainte-Marie “Le Barrage” is located on a sandy mound in one of the meanders of the river Oise. In spite of the significant erosion which removed the upper levels, two groups of pits (ST 7 and 16) can be clearly distinguished 200 meters apart. Their morphology and the analysis of the different corpora of artefacts suggest that the southern group is identifiable as a series of lateral pits alongside houses, and that the northern group represents structures possibly involving craft industries. The study of the pottery and the flints points to an occupancy covering two separate chronological stages: Early BVSG for the southern area, and Late BVSG for the northern group. As for the study of the fauna, it reveals a certain complementarity between the types of detritus, which strengthens the hypothesis of separate functional spaces in the dwellings. The numerous remains of ichthyofauna (1600 fish bones) make it possible for the first time in this area to study the contribution of this food to the diet. Lastly, the existence of four burials in “empty space” must be taken into account, especially that of a woman’s tomb with exceptional grave goods. This site fits into the spatial analysis of this part of the valley which has been the object of study for nearly 30 years, and which has yielded a dozen or so Early Neolithic occupancies.