New Jersey currently utilizes 10 area codes. When first established by AT&T and the Bell System in 1947, 201 covered the entire state of New Jersey. The most recently added was 640 in 2018 as an overlay to 609. Today, 973 is the most populated with an estimated 1.9 million of the state's 8.8 million residents.
Sources: , telecom providers, and the .