Matthew 4:25 - Albert Barnes' Notes on the Bible

From Decapolis - Decapolis was the name of a region of country in the bounds of the half-tribe of Manasseh, mainly on the east of Jordan. It was so called because it included 10 cities - the meaning of the word Decapolis in Greek. Geographers generally agree that Scythopolis was the chief of these cities, and was the only one of them west of the Jordan; that Hippo (Hippos), Gadara, Dion (or Dios), Pelea (or Pella), Gerasa (or Gergesa), Philadelphia, and Raphana (or Raphanae), were seven of the remaining nine, and the other two were either Kanatha and Capitolias, or Damascus and Otopos. These cities were inhabited chiefly by foreigners (Greeks) in the days of our Saviour, and not by Jews. Hence, the keeping of swine by the Gergesenes Matthew 8:30-33, which was forbidden by the Jewish law.