Built by the Byzantines in the 14th century, Kastanitsa castle sits on a height of 840 meters, on the slopes of mount Parnon, in Kastanitsa village. Today remain the ruins of the castle's tower that was destroyed in 1948, during the civil war. It was an important piece of defencive fortification, since it oversaw the road from Argolis to Lakonia. It had a significant role during the Greek Rebellion, while before it had begun, it was being maintained by the captain Kapsampelis.

Today, entrance is free. The people of Kastanitsa have paved and fenced the road from the village to the castle's ruins.