Area code 484 is an overlay of 610 and serves southeastern Pennsylvania, including Allentown, Reading, Bethlehem, and the western suburbs of Philadelphia. Introduced in 1999, 484 was implemented to meet increasing demand for phone numbers in this historically industrial and rapidly suburbanizing region. Ten-digit dialing is required. While 610 carries legacy recognition, 484 has become widely used across residential and business lines. Area code 484 reflects the continuing growth and modernization of Pennsylvania’s Lehigh Valley and suburban Philadelphia, bridging the region’s rich past with its evolving economic and cultural identity.