Transition areas between one metro area and the other

[thebeloitmoderate]

I.E Trenton and Mercer County is the transition point between the NYC and Philly metro areas

[thebeloitmoderate]

Southernmost Missouri/Blytheville Arkansas begins the transition from the Jonesboro, AR metro area to the Memphis area even if there is not a lot of suburbs/sprawl in that area.
Zapata county is the first true RGV county if you drive southeast on US 83 without crossing the Mexico border

[thebeloitmoderate]

Speaking of transitions depending what you drive in I-95 New Haven, CT begins/ends the NYC metro area as it has both it's own tv market and NYC tv stations even though it is the same distance to NYC as from Trenton.
Also Going east from Reading or Allentown though SE you go from the Lehigh Valley into the Philadelphia suburbs of Montgomery County.
Dekalb, IL has Rockford TV/Radio even though it is more associated with the Chicagoland region than the Rockford area

[thebeloitmoderate]

Northernmost LA county begins the transition from the L.A metro area to the Bakersfield metropolitan area