Area codes 610, 484, and 835

The numbering plan area (NPA) includes regions to the west of Philadelphia and the cities Allentown, Bethlehem, and Reading.

The central office prefixes were 267 at Denver, 445 at Terre Hill, and 484 at Adamstown with 267 being renumbered as 717-336 because 717-267 was already in use at Chambersburg.

This was intended as a long-term solution, but further growth in the region over the subsequent five years, and the proliferation of cell phones and pagers, spurred the introduction of area code 484 as an overlay for the 610 region on June 5, 1999, along with the introduction of mandatory ten-digit dialing.

However, newly developed, more efficient number pooling measures were introduced instead, eliminating the immediate need for the new area code.

[3] Area code 835 was eventually approved by the Public Utility Commission on December 2, 2021.

Area code 484 Area code 716 Area code 585 Area code 607 Area code 845 Area codes 973 and 862 Area code 908 Area codes 410 and 443 Area code 302 Area codes 240 and 301 Area codes 304 and 681 Area codes 330 and 234 Area code 440 Area code 724 Area code 878 Area code 724 Area code 814 Area codes 272 and 570 Area codes 610, 484, and 835 Area code 856 Area codes 215, 267, and 445 Area codes 609 and 640 Area codes 223 and 717 Area code 412
Pennsylvania (blue) with numbering plan area 484 shown in red.