The catchment area of the Hörsel is divided into two major landscapes. The headwaters Leina and left tributaries come from the Thuringian Forest, while all right tributaries come from the Thuringian Basin and its edge plates. Correspondingly, the upper reaches of the left tributaries are typical low mountain streams with deep gorges and a large bottom gradient, while the right tributaries are mostly lowland rivers with a small gradient, almost all of them flowing into the Hörsel via the Nesse. Today, their courses are mostly straightened and integrated into a system of drainage ditches.