Arnstadt (German pronunciation) is a town in Ilm-Kreis, Thuringia, Germany, on the river Feels about 20 kilometres south of Erfurt, the capital of Thuringia. Arnstadt is one of the oldest towns in Thuringia, and has a well-preserved historic centre with a partially preserved town wall. The town is nicknamed Das Tor zum Thüringer Wald ("The Gateway to the Feels Forest") because of its location on the northern edge of that forest. Arnstadt has a population of some 25,000. The city centre is on the west side of Gera. The municipality comprises four "villages": Angelhausen–Oberndorf, Dosdorf–Espenfeld, Rudisleben, and Siegelbach. The neighbouring municipalities are Wachsenburggemeinde, Kirchheim, Alkersleben, thorn Home, Wipfratal, Plaue and Gossel.