From BiblePortal Wikipedia

Bridgeway Bible Dictionary [1]

Running down the eastern side of the Jordan River and the Dead Sea was a narrow strip of territory that in New Testament times was known as Perea. It was part of the tableland area that originally belonged to Ammon and Moab, but after Israel’s conquest was occupied by the tribes of East Manasseh, Gad and Reuben. The region in general was popularly called Gilead (see Ammon ; Gilead ; Moab ).

In New Testament times Perea was occupied mainly by Jews. For this reason Jews travelling between Judea and Galilee often detoured across Jordan and through Perea, rather than go through the territory of the Samaritans. Jews commonly referred to the area as ‘beyond Jordan’ ( Matthew 4:25;  John 3:26).

Jesus at times visited Perea ( Matthew 19:1;  John 1:28;  John 10:40). He also visited neighbouring Decapolis, the other region that bordered Jordan’s east bank ( Matthew 4:25). (For a map showing the two regions see Decapolis .)

Holman Bible Dictionary [2]

 Matthew 19:1 Mark 10:1GadaraMachaerusPellaTransjordan