The Titisee is a lake in the southern Black Forest in Baden-Württemberg. It covers an area of 1.3 km2 and is an average of 20 m (66 ft) deep. It owes its formation to the Feldberg glacier, the moraines of which were formed in the Pleistocene epoch and nowadays form the shores of the lake. The lake's outflow, at 840 m (2,760 ft) above sea level, is the River Gutach, which merges with the Haslach stream below Kappel to form the Wutach. The waters of the Titisee thus drain eventually into the Upper Rhine between Tiengen and Waldshut. On the north shore lies the spa town of the same name, today a part of the municipality of Titisee-Neustadt.

At 1,493 metres (4,898 ft) the Feldberg in the Black Forest is the highest mountain in Baden-Württemberg, and the highest in Germany outside of the Alps and Bavaria. The local municipality of Feldberg was named after the mountain.