Buy a Local Phone Number – Area Code 331 (Naperville, Illinois)

Serving Naperville and Chicago’s western suburbs, area code 331 entered service in 2007 as an overlay on 630. The change followed the 1996 split that had carved 630 out of 708, and it addressed numbering pressure created by suburban expansion, wireless adoption, and new enterprises along the I-88 corridor. With the overlay came mandatory ten-digit dialing; no geographic boundaries shifted, but carriers began assigning the new code alongside existing exchanges across DuPage, Kane, Kendall, and Will counties. The arrangement preserved continuity for long-standing landlines while allowing growth in fast-developing communities such as Aurora, Wheaton, and Bolingbrook.

Naperville’s regional role evolved from a river milling town into a hub of educated, commuter-connected professionals, anchored by North Central College and proximity to Argonne National Laboratory and Fermilab, which shaped a STEM-leaning labor market. Late-20th-century corporate campuses and Metra’s BNSF line fostered a diversified economy and drew increasingly international populations, reflected in diverse restaurants, faith centers, and cultural events.

• Technology, software, and R&D along the Illinois Technology and Research Corridor
• Energy, utilities, and engineering services, including gas distribution and grid support
• Healthcare networks, medical devices, and life-science suppliers
• Finance, insurance, and professional services for regional headquarters
• Logistics and distribution linked to I-88, I-355, and nearby intermodal hubs