Jamieson, Fausset and Brown on Mark 5:11

11. Now there was there, nigh unto the mountains--rather, "to the mountain," according to what is clearly the true reading. In Mt 8:30, they are said to have been "a good way off." But these expressions, far from being inconsistent, only confirm, by their precision, the minute accuracy of the narrative.

a great herd of swine feeding--There can hardly be any doubt that the owners of these were Jews, since to them our Lord had now come to proffer His services. This will explain what follows.