Charles Ellicott Commentary Matthew 4:25

"And there followed him great multitudes from Galilee and Decapolis and Jerusalem and Judaea and [from] beyond the Jordan." — Matthew 4:25 (ASV)

Decapolis — The district with this name was formed by the Romans after their first conquest of Syria in 65 B.C. and, roughly speaking, included an area of land east and southeast of the Sea of Galilee. The ten cities from which the region took its name are listed by Pliny (verse 18)—though with the reservation that others gave different lists—as Scythopolis, Hippos, Gadara, Pella, Philadelphia, Gerasa, Dion, Canatha, Damascus, and Raphana.

Of these cities, only Gadara (Matthew 8:28; Mark 5:1; Luke 8:26) and Gerasa (which appears in some manuscripts of the Matthew passage) are mentioned in the Gospels. Damascus is prominent in the book of Acts, but the statement by Josephus (B. J. iii. 9, § 7) that Scythopolis was the largest of the ten towns makes it almost certain that he did not include Damascus in his list.