Edessa was situated on a ridge in the middle of a ring of hills surrounded by a fertile plain, and was therefore considered to be favourably situated.[3][4] The ridge in turn was an extension of Mount Masius, part of the Taurus Mountains of southern Asia Minor.[3] The city was located at a crossroads; the east-west highway from Zeugma on the Euphrates to the Tigris, and the north-south route from Samosata (modern-day Samsat) to the Euphrates via Carrhae (modern-day Harran) met at the ridge where Edessa was located.[3]