Area code 610 serves southeastern Pennsylvania, including cities such as Allentown, Reading, Bethlehem, and Chester. Created in 1994 from a split of area code 215, it helped accommodate the growing population and expanding suburbs of Philadelphia. In 1999, area code 484 was introduced as an overlay, making ten-digit dialing necessary. The 610 area includes the Lehigh Valley and parts of the Main Line, with a strong presence in education, manufacturing, and healthcare. It is a highly recognizable and frequently used area code in the region, associated with both historical towns and modern suburban development.