Forggensee
Forggensee earns its colour honestly: the light sandy limestone subsoil beneath the water turns it a shade somewhere between deep blue and pale turquoise, depending on the hour and the cloud cover. At 15.2 square kilometres it is the largest reservoir in Germany by area, yet it sits so close to Füssen — five minutes by car, or a leisurely bike ride — that it functions almost as the town's front garden.
What makes it strange, in the best way, is what lies underneath. The lake didn't exist before 1954. Where the water now sits, there were once hamlets, farms, and a stretch of the Roman road Via Claudia Augusta. The name itself belongs to Forggen, one of the villages that was flooded to make this place.
💛 What travellers fall for
People who return tend to time it deliberately: summer for the sailing and the boat trips aboard MS Füssen or the smaller MS Allgäu, winter for the uncanny experience of walking the drained basin. In winter you can look for material pits left by Roman road builders along the old Via Claudia Augusta route — the north shore stays warmest for swimming in season, and the Füssen end runs cold from Lech snowmelt.
Deals in Forggensee
Book directly at the providerHow Forggensee came to be
Construction of the Roßhaupten Dam began in early 1951, led by Bayerische Wasserkraftwerke (BAWAG), a company founded in 1940 to harness power from the Lech and its neighbouring rivers. The dam's purpose was practical: control spring flooding from snowmelt and generate electricity. The lake reached its full level for the first time in spring 1954.
The human cost was considerable. Thirty-two residential buildings housing 256 people across the villages of Brunnen, Deutenhausen, and Forggen were submerged; 32 families from the Lower Weidachsiedlung were fully relocated. Residents negotiated the 1952 Schwangau Agreement with BAWAG, securing new farms or houses nearby. The lake takes its name from the hamlet of Forggen, which now lies at its bottom. The dam was renovated by Uniper — at a cost of approximately 30 million euros — and the lake was reflooded in 2019.
Who and what shaped it
Landmark buildings
Plan your visit
On the map
When to go
Summer days from June through September are mild, with August averaging around 22°C at the high end and July offering the longest sunshine hours — close to nine and a half hours daily. Water temperature rarely exceeds 20°C even at its warmest, so swimming is refreshing rather than warm. Winter drains the lake and brings low light but a genuinely unusual landscape.
Right now
Background & history adapted from Wikipedia (CC BY-SA) · specs from Wikidata (CC0) · weather from Open-Meteo · map data © OpenStreetMap contributors · photos from Wikimedia Commons / Unsplash with per-image credit. No third-party reviews or social posts reproduced.