area code overlay

An area code overlay occurs when a new area code is introduced to cover the same geographic region as an existing one. Instead of dividing the region into separate zones, both codes coexist, meaning new phone numbers might have the new area code while existing ones retain the old. This often requires residents to dial the full 10-digit number (area code + number) for local calls. Overlays help meet demand for phone numbers without changing current numbers or dividing communities, but they may also introduce some visual complexity to dialing and calling patterns.