The Castle of Oria is located northwest of Tourkoleka, on a hill at the foothills of Mount Ellinitsa, in a rugged and hard‑to‑reach position. The castle lies near the border between Messenia and Arcadia and is believed to have been built on the site of the ancient Messenian city of Amfeia. The earliest reference to it dates to 1264, when defeated Byzantine officials were taken there as prisoners after the Battle of Makryplagi. It was certainly standing by 1297, when it is mentioned in the French version of the Chronicle of the Morea as a Greek fortress.

The castle has two entrances, a western one at the location known as Nogk and an eastern one. Within the enclosure, substantial remains of buildings, churches, towers, and cisterns are preserved. Among them are the remains of the churches of the Dormition of the Virgin and of Faneromeni. The settlement associated with the castle developed on its western slope, within the outer fortification wall, and dates to the late Byzantine period.

According to the Aragonese Chronicle, the castle was besieged in 1374 by the bailli of the Morea during the reign of Princess Joanna I of Naples. The Franks were eventually forced to abandon the siege, unable to capture such a strong fortress. In 1460, Sultan Mehmed II the Conqueror besieged, captured, and destroyed the castle, massacring most of its inhabitants. The site is mentioned again later, when Ioannis Gennaios, the son of Theodoros Kolokotronis, sought refuge there.