The Lehigh Valley‘s main cities include Allentown, Bethlehem, and Easton. This area is known as the Allentown-Bethlehem–Easton metropolitan area. The traditional boundaries of the region include The Poconos in the north, The Delaware River in the east, Berks County, Montgomery County, and Bucks County in the south.

Previously, however, portions of upper Bucks County around Quakertown as well as parts of eastern Berks County along with southern Carbon and Schuylkill Counties in Pennsylvania were considered outer parts.