Froschgrundsee, Reservoir in Rödental, Bavaria, Germany

Froschgrundsee is a reservoir in the town of Rödental, in the German state of Bavaria, surrounded by open meadows and crossed by a railway bridge. A marked circular trail runs the full length around the water, making it easy to explore the entire shoreline on foot.

Froschgrundsee was built between 1982 and 1986 as a flood retention basin protecting Coburg from the Itz, Effelder and Grümpen; planning required agreements with East Germany and it was seen as an inner-German model project. It cost 43 million DM. The 798-metre Talbrücke Froschgrundsee, a railway viaduct with a 270-metre arch, was built over the lake between 2006 and 2011 for the Nuremberg–Erfurt high-speed line.

The lake draws locals who come to walk, watch birds, and spend time outdoors along the shore. The circular path around the water is a regular weekend destination for families from the surrounding villages.

The reservoir is managed by the Wasserwirtschaftsamt Kronach, and the Staatsstraße 2206 runs west around the water. A circular path leads around the lake for walking and cycling, and swimming and water sports are possible in summer. The dam itself is an 18-metre-high, 350-metre-long earth embankment.

In warmer weather, blue-green algae can grow in the water, turning it a different color and making swimming unsafe. Warning signs are posted around the lake on those days, so it is worth checking conditions before planning a visit.