Matthew 3:5

3:5 Then people from Jerusalem, as well as all Judea and all the region around the Jordan, were going out to him,

Mark 1:4-5

1:4 In the wilderness John the baptizer began preaching a baptism of repentance for the forgiveness of sins. 1:5 People from the whole Judean countryside and all of Jerusalem were going out to him, and he was baptizing them in the Jordan River as they confessed their sins.

John 1:28

1:28 These things happened in Bethany across the Jordan River where John was baptizing.

John 3:26

3:26 So they came to John and said to him, “Rabbi, the one who was with you on the other side of the Jordan River, about whom you testified – see, he is baptizing, and everyone is flocking to him!”