Hertenstein Castle is a ruined spur castle approximately 900 metres (3,000 feet) southwest of the village of Billingsbach, part of the municipality of Blaufelden, in the district of Schwäbisch Hall in the state of Baden-Württemberg, Germany.

The castle is located on a steep hill above the confluence of two streams (the Billingsbach and the Rötelbach) at an elevation of 442 metres (1,450 feet).

The main approach of the castle to the northeast was protected by an 80-metre (260-foot) long artificial moat running from the steep slopes to the north towards the neighbouring hill in the south.

The existence of a castle is only documented as late as 1314 when a certain Eberhard von Hertenstein, lord of Billingsbach and vassal of the counts of Hohenlohe, appeared as a witness in a charter.

[4] A trading route leading from Künzelsau through the valley of the Jagst towards Schrozberg and Rothenburg ob der Tauber passed through Billingsbach, where it crossed two streams.