What is what area code is 571?

Area code 571 is a telephone area code that serves parts of Northern Virginia in the United States. It overlays the existing area code 703, meaning both area codes cover the same geographic region. This overlay was implemented due to the increasing demand for phone numbers in the area.

It mainly covers areas within:

Since it's an overlay, when making a call within this region, you must dial all 10 digits (area code + the seven-digit phone number) regardless of whether you are calling someone with the 703 or 571 area code.