Problem: The first three Gospels (Matthew, Mark, and Luke) each give an account of Jesus healing demoniacs. Matthew states that the place where the healing took place was the country of the Gadarenes. However, Mark and Luke say it was in the country of the Gerasenes.
Solution: There is a textual problem here. The critical text of the Greek NT (Nestle-Aland/United Bible Societies) renders Mark and Luke the same as Matthew, namely, in the country of the “Gadarenes.” However, some manuscripts give the name of the country as the Gerasenes. It is possible to account for the variant reading in these manuscripts as a scribal error. Gadara may have been the capital of the region, and Matthew therefore referred to the area as the “country of the Gadarenes” because the people of that region, whether they lived in Gadara or not, were identified as Gadarenes. Mark and Luke were perhaps giving a more general reference to the country of the Gerasenes, which was the wider area in which the incident occurred. However, a scribe, confusing the reference in Matthew as a reference to the town instead of the people of the region, may have attempted to correct the manuscripts and altered the references to make them uniform. It seems that the best textual evidence is in favor of Gadara, although there are varying opinions among commentators. There is no contradiction or error here, because the problem developed as a result of transcription, and there is no evidence to demonstrate that there was a conflict in the original manuscripts.
“And when he was come to the other side into the country of the Gergesenes, there met him two possessed with devils, coming out of the tombs, exceeding fierce, so that no man might pass by that way. And, behold, they cried out, saying, What have we to do with thee, Jesus, thou Son of God? art thou come hither to torment us before the time? And there was a good way off from them an herd of many swine feeding. So the devils besought him, saying, If thou cast us out, suffer us to go away into the herd of swine. And he said unto them, Go. And when they were come out, they went into the herd of swine: and, behold, the whole herd of swine ran violently down a steep place into the sea, and perished in the waters. And they that kept them fled, and went their ways into the city, and told every thing, and what was befallen to the possessed of the devils. And, behold, the whole city came out to meet Jesus: and when they saw him, they besought him that he would depart out of their coasts. (Matt 8:23-34)”