The Nesse is a 54.5-kilometre-long (33.9 mi) tributary of the Hörsel in the southern Thuringia. Strictly speaking, it represents a second, right main branch of the Hörsel, which brings about as much water to join the Hörsel as the Hörsel itself and drains an even larger catchment area. The Nesse is a typical lowland river with an average bed gradient of only about 1.5 ‰. According to the it has the status of a first order watercourse and is therefore under the maintenance obligation of the Free State of Thuringia.