<p>On a historical scale, European river systems have been heavily transformed since the eighteenth century for navigation and flood protection purposes. Although numerous geohistorical studies have been undertaken to characterise river modifications, many have focused on channel evolution to the detriment of the floodplain. This paper addresses this shortcoming by examining the case of the Bassée floodplain in the Seine River valley (France). In this area, recent studies have quantified the changes brought to the river’s minor bed as a result of navigation works. Our aim is to supplement these studies by extending the approach to the floodplain, using land use evolution as a proxy for hydrological changes. We used quantitative (i.e. GIS processing) and qualitative (i.e. analysis of historical records) approaches to identify and interpret changes in land use between the middle of the nineteenth century and 1987. Results show three stages in the transformation of the floodplain: (i) controlling soil moisture, (ii) disputes over lateral connectivity and (iii) disconnection from the river. They confirm the impact of hydraulic and navigation works on the hydrological characteristics of the floodplain, as revealed by modifications in agricultural land use. Moreover, they point to broader, multiscale factors of socio-environmental change whose effects persist today.</p>