Area code 331, overlain with 630, serves portions of Chicago’s near and far western suburbs. 10-digit dialing is required in these areas.
- 331-201
- Cell Number
- Downers Grove, IL
- 331-207
- Landline Number
- Yorkville, IL
- 331-214
- Cell Number
- Downers Grove, IL
- 331-240
- Landline Number
- West Chicago, IL
- 331-251
- Cell Number
- Downers Grove, IL
- 331-281
- Landline Number
- Naperville, IL
- 331-444
- Landline Number
- Naperville, IL
- 331-481
- Cell Number
- Downers Grove, IL
- 331-625
- Cell Number
- Downers Grove, IL
- 331-777
- Landline Number
- Downers Grove, IL
- 331-888
- Landline Number
- Warrenville, IL