Lörrach is a Landkreis (district) in the southwest of Baden-Württemberg, Germany. Neighboring districts are Breisgau-Hochschwarzwald and Waldshut. To the west it borders the French département Haut-Rhin ; to the south the Swiss cantons Basel-Stadt , Basel-Landschaft and Aargau .

In 1973 part of the district Müllheim and small parts of the district Säckingen were added to the district, which enlarged the district by about 25% to the current size.

The north-east of the district is part of the Hochschwarzwald, the highest part of the Black Forest . In the west is the Markgräfler Hügelland, in the south the Dinkelberg, both lower hilly areas.