{"area_code":"331","type":"geographic","status":"active","country":"US","region":"Illinois","region_code":"IL","principal_city":"Aurora","cities":["Aurora","Naperville","Bolingbrook","Wheaton","Downers Grove","Elmhurst","Lombard","Bartlett","Carol Stream","Streamwood","Hanover Park","Addison","Batavia","Bensenville","Bloomingdale","Darien","Glen Ellyn","Glendale Heights","Lisle","North Aurora","Roselle","Saint Charles","Villa Park","West Chicago","Westmont","Woodridge"],"timezone":"America/Chicago","timezone_label":"Central Time","current_local_time":"2026-08-04 16:04:01","ten_digit_dialing":true,"service_type":null,"overlay_codes":["630"],"nearby_codes":["630","312","773","872","224","847"],"summary":"Area code 331 covers Aurora and nearby cities including Naperville, Bolingbrook, Wheaton in Illinois, in the Central Time.","carrier_summary":{"nxx_prefixes":222,"blocks":2294,"wireless_pct":45,"top_carriers":[{"name":"ONVOY, LLC","blocks":523},{"name":"T-MOBILE USA, INC.","blocks":322},{"name":"NEW CINGULAR WIRELESS PCS, LLC - IL","blocks":309},{"name":"CELLCO PARTNERSHIP DBA VERIZON WIRELESS - IL","blocks":293},{"name":"BANDWIDTH.COM CLEC, LLC - IL","blocks":171},{"name":"ONVOY SPECTRUM, LLC","blocks":74}],"per_number":"https://areacode.fyi/api/v1/carrier/{number}"},"canonical_url":"https://areacode.fyi/331","source":"North American Numbering Plan Administrator via areacode.fyi","data_date":"2026-08-02"}