Matthew 8:28-34

28 When He had come to the other side, to the country of the Gergesenes, there met Him two demon-possessed men, coming out of the tombs, exceedingly fierce, so that no one could pass that way.

29 And suddenly they cried out, saying, “What have we to do with You, Jesus, You Son of God? Have You come here to torment us before the time?”

30 Now a good way off from them there was a herd of many swine feeding.

31 So the demons begged Him, saying, “If You cast us out, permit us to go away into the herd of swine.”

32 And He said to them, “Go.” So when they had come out, they went into the herd of swine. And suddenly the whole herd of swine ran violently down the steep place into the sea, and perished in the water.

33 Then those who kept them fled; and they went away into the city and told everything, including what had happened to the demon-possessed men.

34 And behold, the whole city came out to meet Jesus. And when they saw Him, they begged Him to depart from their region.

Gergesenes (v.28) — Gerasa was a large territory in Perea in which was located near Gerash, one of the cities of Decapolis. Matthew states that He came into the region of the Gadarenes. Gadara was a town in Gerasa some six miles southeast of the Sea of Galilee. — Pentecost, page 221.

demons (v.28) — fallen angels who followed Satan — there were two men, but many demons. In Mark 5:9, the demons give their name as Legion, which means many.

the time (v.29) — of judgment (Revelation 20:10)

Son of God (v.29) — The demons recognized Christ (James 2:19) and also knew their ultimate fate.

swine (v.30) — These unclean beasts were not considered fit for food, in accordance with Mosaic Law (Leviticus 11:7). But they were apparently tended by degraded Jews who sought gain by selling them to the Gentiles. Such became the occupation of the prodigal (Luke 15:15). According to the Law, such a calling was absolutely illegal in the land of Israel. — Ironside, page 99

This account is also recorded, with more details, in Mark 5:1-20 and Luke 8:26-39, but they only mention the one man who went on to become a follower of Christ.