Globally, hydrological connectivity between rivers and their floodplains has been reduced by river flow management and land transformation. The Saskatchewan River Delta is North America's largest inland delta and a hub for fish and fur production. To determine the influence of connectivity on limnology within this northern floodplain, water chemistry and stable isotopes (␦ 18 O and ␦ 2 H) were analyzed during the winter of 2014 in 26 shallow lakes along a hydrological gradient. A total of five lake connectivity categories were determined by optical remote sensing imagary of surface water coverage area from years of varying flood intensities. Accuracy of categories was verified by degree of 18 O and 2 H enrichment within lakes. Both isotopes showed marked successional enrichment between connectivity categories, with more isolated lakes exhibiting greater enrichment. Water chemistry in lakes with greater connectivity to the main channel were characterized by higher pH, dissolved oxygen, nitrates, and sulfates and lower total nitrogen, total phosphorus, and ammonium compared with more isolated lakes. These findings illustrate how connectivity influences water chemistry in northern floodplain lakes and how it might determine the suitability of these lakes as winter refuge for fishes. Additionally, our study provides supporting evidence for the effective use of optical remote sensing imagery, an inexpensive and accessible source of data for researchers, when determining connectivity characteristics of large northern floodplain systems. Additionally, this study provides further evidence that the inundation of floodplain lakes by river water during peak discharge has an impact on the conditions within the lakes long into the winter ice-cover season. Understanding the year-round influence of river-floodplain connection is imperative for assessing potential impacts of climate change and future water regulation on such ecosystems.Résumé : À l'échelle planétaire, la gestion des débits des rivières et la transformation du territoire ont entraîné une diminution de la connectivité hydrologique entre les rivières et les plaines inondables. Le delta de la rivière Saskatchewan est le plus grand delta intérieur d'Amérique du Nord et une plaque tournante pour la production de poissons et de fourrures. Afin de déterminer l'influence de la connectivité sur la limnologie dans cette plaine inondable septentrionale, la chimie de l'eau et ses isotopes stables (␦ 18 O et ␦ 2 H) ont été analysés durant l'hiver 2014 dans 26 lacs peu profonds le long d'un gradient hydrologique. Cinq catégories de connectivité des lacs ont été établies au total sur la base d'images optiques de télédétection des aires recouvertes par les eaux de surface pour des années caractérisées par différentes intensités des crues. L'exactitude des catégories a été vérifiée à la lumière du degré d'enrichissement en 18