Expositor's Bible Commentary Commentary Mark 7:31

"And again he went out from the borders of Tyre, and came through Sidon unto the sea of Galilee, through the midst of the borders of Decapolis." — Mark 7:31 (ASV)

Mark includes this miracle in the Decapolis, a story unique to his gospel, because it connects with the previous story by giving an account of another healing on Gentile territory. The Decapolis was largely Gentile, but many Jews also lived there.