Springs are important habitats and determine the characteristics of headwater streams. However, they are rarely studied and usually not included in monitoring programs. Our study characterizes the sources of three large rivers and contributes to the knowledge about the biggest East European drainage divide. The catchment area is characterized by dense forests, which are rich in swamps and mires. The paludified catchment is typical for the rivers in this region and it is also determining the physicochemistry of the water. We provide a first dataset about the physicochemical conditions of the sources of Volga, Dnieper, and Western Dvina, which should build a basis for further analyses of the springs of these large rivers. We suggest that monitoring the sources of the large rivers in the Valdai hills should be considered as an extension of the existing monitoring programs.