Charles Ellicott Commentary Mark 5:13

"And he gave them leave. And the unclean spirits came out, and entered into the swine: and the herd rushed down the steep into the sea, [in number] about two thousand; and they were drowned in the sea." — Mark 5:13 (ASV)

They were about two thousand.—The number, which is peculiar to Saint Mark, may be noted as another instance of his graphic accuracy in detail.