Decapolis

ten cities = deka, ten, and polis, a city, a district on the east and south-east of the Sea of Galilee containing "ten cities," which were chiefly inhabited by Greeks. It included a portion of Bashan and Gilead, and is mentioned three times in the New Testament (Matt 4:25; Mark 5:20; 7:31). These cities were Scythopolis, i.e., "city of the Scythians", (ancient Bethshean, the only one of the ten cities on the west of Jordan), Hippos, Gadara, Pella (to which the Christians fled just before the destruction of Jerusalem), Philadelphia (ancient Rabbath-ammon), Gerasa, Dion, Canatha, Raphana, and Damascus. When the Romans conquered Syria (B.C. 65) they rebuilt, and endowed with certain privileges, these "ten cities," and the province connected with them they called "Decapolis."

EBD - Easton's Bible Dictionary