The Mummelsee is a cirque lake — a bowl carved into the mountainside by a small Ice Age glacier and then filled with water. It lies at 1,036 m on the western flank of the Hornisgrinde, covers about 3.7 hectares, is roughly 17 metres deep and measures around 800 metres round. It is the largest of the seven cirque lakes that survive in the Black Forest, and thanks to the Black Forest High Road, which runs right past it, by far the easiest to visit.
The water is dark, acidic and peaty — so poor in nutrients that it holds no fish — and the fir forest comes straight down to the shore. That brooding atmosphere is where the legends come from: the Mummeln, water sprites who were said to rise from the lake at night, and the Lake King who ruled them from a palace on the bottom. The name itself most likely comes from the local word for the white water lilies that once grew here.
Top things to do at Mummelsee
Walk the lake loop
The path around the shore is about 800 m long and was rebuilt as a barrier-free trail in 2014, so it works for pushchairs and wheelchairs too. Allow 20–30 minutes. Along the way the Kunstpfad sculpture trail places contemporary artworks among the trees, and information boards tell the lake’s stories.
Take a pedal boat out
A pedal-boat hire operates beside the main car park in the warmer months. Half an hour on the water is the best way to see the lake’s full shape, the cliffs on the Hornisgrinde side and the hotel reflected in the water. Rental depends on the weather and season — check on the day.
Hear the legend of the Mummeln
According to local tradition, the lake maidens came down to the village of Seebach to join the spinning evenings and dances, but always had to be home before midnight. One night they stayed too long — and the lake, it is said, turned red. Grimmelshausen sent his hero Simplicius to the Lake King’s underwater realm in the 17th-century novel Simplicissimus, and Eduard Mörike wrote the poem “Die Geister am Mummelsee”.
Cake on the terrace
The Berghotel Mummelsee has a restaurant, terrace and Black Forest shop right on the water. A slice of Schwarzwälder Kirschtorte — chocolate sponge, kirsch, cherries and cream — with the lake in front of you is the traditional reward for the walk.
How to get to Mummelsee
- By car: the lake is directly on the B500 Black Forest High Road, about 30 km (40–45 minutes) from Baden-Baden and 20 km from Freudenstadt; from the A5 motorway take exit Achern and climb via Kappelrodeck and Seebach. There is a large visitor car park on the south shore (charges apply).
- By bus: regional buses link the Mummelsee with Achern railway station via Seebach (line 7120 at the time of writing) and run along the High Road towards Baden-Baden and Freudenstadt, with extra services at weekends. Check the current timetable before you travel — see our getting here guide.
- On a tour: several day trips from Strasbourg stop at the lake — compare them on our best tours page.
Insider tips
- Arrive before 10:30 or after 16:00 on summer weekends and holidays. Around midday coaches, motorcyclists and day-trippers all converge on the car park.
- The lake sits above 1,000 m: it is often several degrees cooler, windier and wetter than Baden-Baden. Bring a layer even in July.
- Combine the lake with the climb to the Hornisgrinde — the path starts right behind the hotel — to turn a short stop into a half-day walk.
- Swimming is not what the lake is for: the water is cold, acidic and protected. Enjoy it from the shore or a boat.
Best tours & tickets for Mummelsee
These top-rated experiences are the easiest way to see Mummelsee and the rest of the Black Forest:
Small-group day trip from US$245 From Strasbourg: Black Forest and Baden-Baden Day Trip
The best-reviewed way to reach the Mummelsee without a car. An English-speaking guide takes a small group across the Rhine to Baden-Baden, then climbs the Schwarzwaldhochstraße with photo stops before a proper break at the lake for lunch, cake and a walk along the shore.
- Guided stroll through Baden-Baden and the Lichtentaler Allee
- Viewpoints over the Rhine valley on the Black Forest High Road
- Free time and lunch at the Mummelsee
Private day trip from US$512 per group From Strasbourg: Black Forest Day Trip with Lake Mummelsee
Your own vehicle for up to four people and a relaxed pace: Baden-Baden in the morning, the Black Forest High Road at midday, lunch and Black Forest cake at the Mummelsee, then down the Baden wine route to the flower-hung village of Sasbachwalden. An audio guide in English, French or Spanish fills in the stories.
- Private car or van with pickup in Strasbourg
- Baden-Baden, the High Road and a long stop at the Mummelsee
- Wine-village finale in half-timbered Sasbachwalden
Private tour from US$888 per group The Best in Baden-Baden and Blackforest
A private, flexible day for up to six people starting in the spa town itself. The guide shapes the route around your interests — thermal baths, wine cellars, Black Forest food and the forest roads above Baden-Baden — which makes it the natural choice if you want someone else to handle the driving.
- Casino, Kurhaus and Lichtentaler Allee with a private guide
- Black Forest food and historic wineries
- Forest scenery tailored to your group
