Hyrcania, Archaeological site in Bethlehem Governorate, Israel.

Hyrcania is a ruined fortress and monastery on an isolated hill rising about 200 metres above the Hyrcania valley, roughly 5 km west of Qumran and 16 km east of Jerusalem. The site preserves Hasmonean and Herodian fortification walls, a tower, and water cisterns, along with the remains of the Byzantine monastery of Kastellion, including a cave with faded wall paintings of named Christian saints.

The site began as a fortress, was later reinforced by Herod, and then held prisoners who opposed the ruler. It eventually transformed into a monastery that served religious purposes for centuries afterward.

The Arabic name Khirbet el-Mird and the Greek Kastellion both mean 'little castle', a name kept from the fortress. The monastery was a cenobium of hermits dependent on Mar Saba, 4 km to the south-west. A cache of 7th- and 8th-century monastic papyri found here in 1950 is now held in Leuven and the Rockefeller Museum.

Reaching the site requires effort, as it sits on remote terrain with a challenging walk to get there. Bring sturdy shoes and plenty of water, since shade is scarce and there are few facilities at the location.

Four rock-cut tunnels were found in a nearby wadi between 2000 and 2006. Two were cleared, yielding a Hasmonean clay pot, Hasmonean coins, and the skeleton of a young woman with sword cuts; they end abruptly at 80 and 120 metres.