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Area Code 312

Browse available prefixes, locations, carriers, and quick path links into deeper phone number pages for this area code. Area-code research is one of the most important parts of reverse phone lookup because it gives visitors a geographic starting point before they inspect a full number.

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200Prefixes Listed
IllinoisLocation
United StatesCountry
312Area Code
Area Code Overview
Area Code312
Primary LocationIllinois
CountryUnited States
Prefix Coverage200 listed prefixes
Prefixes in 312
312-201
Chicago
Ameritech Illinois
Landline
312-202
Chicago
Ameritech Illinois
Landline
312-203
Willowbrook
New Cingular Wireless Pcs Llc - Il
Wireless
312-204
Chicago
Ameritech Illinois
Landline
312-205
Chicago
Allegiance Telecom Inc. - Il
Landline
312-206
Willowbrook
New Cingular Wireless Pcs Llc - Il
Wireless
312-207
Chicago
Ameritech Illinois
Landline
312-208
Willowbrook
New Cingular Wireless Pcs Llc - Il
Wireless
312-209
Elgin
Cellco Partnership Dba Verizon Wireless - Il
Wireless
312-212
Chicago
Ameritech Illinois
Landline
312-213
Willowbrook
New Cingular Wireless Pcs Llc - Il
Wireless
312-214
Chicago
Ameritech Illinois
Landline
312-215
Schaumburg
New Cingular Wireless Pcs Llc - Il
Wireless
312-216
Chicago
Globalcom Inc.-il
Landline
312-217
Lombard
United States Cellular Corp. - Illinois
Wireless
312-218
Willowbrook
New Cingular Wireless Pcs Llc - Il
Wireless
312-219
Chicago
Bandwidth.com Clec Llc - Il
Landline
312-220
Chicago
Ameritech Illinois
Landline
312-221
Bridgeview
Sprint Spectrum L.p.
Wireless
312-222
Chicago
Ameritech Illinois
Landline
312-223
Chicago
Ameritech Illinois
Landline
312-224
Arlington Heights
Broadwing Communications Llc - Il
Landline
312-225
Chicago
Ameritech Illinois
Landline
312-226
Chicago
Ameritech Illinois
Landline
312-227
Chicago
Ameritech Illinois
Landline
312-228
Chicago
Ameritech Illinois
Landline
312-229
Chicago
Ameritech Illinois
Landline
312-230
Chicago
Ameritech Illinois
Landline
312-231
Schaumburg
New Cingular Wireless Pcs Llc - Il
Wireless
312-232
Chicago
American Messaging (am) Inc.
Landline
312-233
Chicago
Ameritech Illinois
Landline
312-234
Chicago
Ameritech Illinois
Landline
312-235
Chicago
Ameritech Illinois
Landline
312-236
Chicago
Ameritech Illinois
Landline
312-237
Hickory Hills
Cellco Partnership Dba Verizon Wireless - Il
Wireless
312-238
Arlington Heights
Broadwing Communications Llc - Il
Landline
312-239
Chicago
At&t Local
Landline
312-240
Chicago
Ameritech Illinois
Landline
312-241
Willowbrook
New Cingular Wireless Pcs Llc - Il
Wireless
312-242
Chicago
Teleport Communications America Llc - Il
Landline
312-243
Chicago
Ameritech Illinois
Landline
312-244
Chicago
Ameritech Illinois
Landline
312-245
Chicago
Ameritech Illinois
Landline
312-246
Schaumburg
New Cingular Wireless Pcs Llc - Il
Wireless
312-247
Chicago
Globalcom Inc.-il
Landline
312-249
Hinsdale
Usa Mobility Wireless Inc.
Wireless
312-250
Hinsdale
Usa Mobility Wireless Inc.
Wireless
312-251
Chicago
Ameritech Illinois
Landline
312-252
Chicago
Allegiance Telecom Inc. - Il
Landline
312-253
Chicago
Allegiance Telecom Inc. - Il
Landline
312-254
Chicago
Allegiance Telecom Inc. - Il
Landline
312-255
Chicago
Ameritech Illinois
Landline
312-256
Chicago
Allegiance Telecom Inc. - Il
Landline
312-257
Elgin
Cellco Partnership Dba Verizon Wireless - Il
Wireless
312-258
Chicago
Ameritech Illinois
Landline
312-259
Willowbrook
New Cingular Wireless Pcs Llc - Il
Wireless
312-260
Bensenville
Mcimetro Access Transmission Services Llc
Landline
312-261
Chicago
Broadwing Communications Llc - Il
Landline
312-262
Chicago
Allegiance Telecom Inc. - Il
Landline
312-263
Chicago
Ameritech Illinois
Landline
312-264
Chicago
Broadwing Communications Llc - Il
Landline
312-265
Chicago
Access One Inc. - Il
Landline
312-266
Chicago
Ameritech Illinois
Landline
312-267
Chicago
Ameritech Illinois
Landline
312-268
Arlington Heights
Broadwing Communications Llc - Il
Landline
312-269
Chicago
Ameritech Illinois
Landline
312-271
Hinsdale
Usa Mobility Wireless Inc.
Wireless
312-272
Hinsdale
Usa Mobility Wireless Inc.
Wireless
312-273
Elgin
Cellco Partnership Dba Verizon Wireless - Il
Wireless
312-274
Chicago
Ameritech Illinois
Landline
312-275
Chicago
Allegiance Telecom Inc. - Il
Landline
312-276
Chicago
Allegiance Telecom Inc. - Il
Landline
312-277
Chicago
Allegiance Telecom Inc. - Il
Landline
312-278
Arlington Heights
Broadwing Communications Llc - Il
Landline
312-279
Bensenville
Mcimetro Access Transmission Services Llc
Landline
312-280
Chicago
Ameritech Illinois
Landline
312-281
Chicago
Global Crossing Local Services Inc.-il
Landline
312-282
Willowbrook
New Cingular Wireless Pcs Llc - Il
Wireless
312-283
Chicago
Global Crossing Local Services Inc.-il
Landline
312-284
Chicago
Xo Illinois Inc.
Landline
312-285
Bridgeview
Sprint Spectrum L.p.
Wireless
312-286
Willowbrook
New Cingular Wireless Pcs Llc - Il
Wireless
312-287
Buffalo Grove
Sprint Spectrum L.p.
Wireless
312-288
Bensenville
Mcimetro Access Transmission Services Llc
Landline
312-289
Hinsdale
Usa Mobility Wireless Inc.
Wireless
312-290
Hinsdale
Usa Mobility Wireless Inc.
Wireless
312-291
Chicago
Ameritech Illinois
Landline
312-292
Chicago
Bandwidth.com Clec Llc - Il
Landline
312-293
Chicago
Ameritech Illinois
Landline
312-294
Chicago
Ameritech Illinois
Landline
312-295
Hinsdale
Usa Mobility Wireless Inc.
Wireless
312-296
Buffalo Grove
Sprint Spectrum L.p.
Wireless
312-297
Chicago
Ameritech Illinois
Landline
312-298
Chicago
Sigecom Llc - Il
Landline
312-299
Hinsdale
Usa Mobility Wireless Inc.
Wireless
312-300
Chicago
Net Talk.com Inc. - Il
Landline
312-301
Willowbrook
New Cingular Wireless Pcs Llc - Il
Wireless
312-302
Chicago
Ameritech Illinois
Landline
312-303
Schaumburg
New Cingular Wireless Pcs Llc - Il
Wireless
312-304
Willowbrook
New Cingular Wireless Pcs Llc - Il
Wireless
312-305
Elgin
Cellco Partnership Dba Verizon Wireless - Il
Wireless
312-306
Chicago
Ameritech Illinois
Landline
312-307
Willowbrook
New Cingular Wireless Pcs Llc - Il
Wireless
312-308
Chicago
Ameritech Illinois
Landline
312-309
Chicago
Ameritech Illinois
Landline
312-310
Elgin
Cellco Partnership Dba Verizon Wireless - Il
Wireless
312-314
Willowbrook
New Cingular Wireless Pcs Llc - Il
Wireless
312-315
Willowbrook
New Cingular Wireless Pcs Llc - Il
Wireless
312-316
Willowbrook
New Cingular Wireless Pcs Llc - Il
Wireless
312-317
Schaumburg
New Cingular Wireless Pcs Llc - Il
Wireless
312-318
Hickory Hills
Cellco Partnership Dba Verizon Wireless - Il
Wireless
312-320
Willowbrook
New Cingular Wireless Pcs Llc - Il
Wireless
312-321
Chicago
Ameritech Illinois
Landline
312-322
Chicago
Ameritech Illinois
Landline
312-323
Chicago
American Messaging (am) Inc.
Landline
312-324
Chicago
Level 3 Communications Llc - Il
Landline
312-325
Chicago
Ameritech Illinois
Landline
312-326
Chicago
Ameritech Illinois
Landline
312-327
Chicago
Xo Illinois Inc.
Landline
312-328
Chicago
Ameritech Illinois
Landline
312-329
Chicago
Ameritech Illinois
Landline
312-330
Willowbrook
New Cingular Wireless Pcs Llc - Il
Wireless
312-331
Schaumburg
New Cingular Wireless Pcs Llc - Il
Wireless
312-332
Chicago
Ameritech Illinois
Landline
312-333
Chicago
American Messaging (am) Inc.
Landline
312-334
Chicago
Globalcom Inc.-il
Landline
312-335
Chicago
Ameritech Illinois
Landline
312-336
Chicago
Ameritech Illinois
Landline
312-337
Chicago
Ameritech Illinois
Landline
312-338
Chicago
Ameritech Illinois
Landline
312-339
Elgin
Cellco Partnership Dba Verizon Wireless - Il
Wireless
312-340
Willowbrook
Cellco Partnership Dba Verizon Wireless - Il
Wireless
312-341
Chicago
Ameritech Illinois
Landline
312-342
Willowbrook
New Cingular Wireless Pcs Llc - Il
Wireless
312-343
Elgin
Cellco Partnership Dba Verizon Wireless - Il
Wireless
312-344
Chicago
Ameritech Illinois
Landline
312-345
Chicago
Ameritech Illinois
Landline
312-346
Chicago
Ameritech Illinois
Landline
312-347
Chicago
Ameritech Illinois
Landline
312-348
Elk Grove Village
Neutral Tandem-illinois Llc - Il
Landline
312-349
Hinsdale
Usa Mobility Wireless Inc.
Wireless
312-350
Elgin
Cellco Partnership Dba Verizon Wireless - Il
Wireless
312-351
Willowbrook
New Cingular Wireless Pcs Llc - Il
Wireless
312-352
Willowbrook
New Cingular Wireless Pcs Llc - Il
Wireless
312-353
Chicago
Ameritech Illinois
Landline
312-354
Schaumburg
New Cingular Wireless Pcs Llc - Il
Wireless
312-355
Chicago
Ameritech Illinois
Landline
312-356
Chicago
Ameritech Illinois
Landline
312-357
Chicago
Ameritech Illinois
Landline
312-359
Hinsdale
Usa Mobility Wireless Inc.
Wireless
312-360
Chicago
Ameritech Illinois
Landline
312-361
Chicago
Ameritech Illinois
Landline
312-362
Chicago
Ameritech Illinois
Landline
312-363
Chicago
Rcn Telecom Services Of Illinois Inc. - Il
Landline
312-364
Chicago
Ameritech Illinois
Landline
312-365
Hinsdale
Usa Mobility Wireless Inc.
Wireless
312-366
Hinsdale
Usa Mobility Wireless Inc.
Wireless
312-367
Hinsdale
Usa Mobility Wireless Inc.
Wireless
312-368
Chicago
Ameritech Illinois
Landline
312-369
Chicago
New Cingular Wireless Pcs Llc - Il
Wireless
312-370
Hinsdale
Usa Mobility Wireless Inc.
Wireless
312-371
Bridgeview
Sprint Spectrum L.p.
Wireless
312-372
Chicago
Ameritech Illinois
Landline
312-373
Chicago
Broadwing Communications Llc - Il
Landline
312-374
Chicago
Ameritech Illinois
Landline
312-375
Chicago
T-mobile Usa Inc.
Wireless
312-376
Chicago
Cbeyond Communications Llc - Il
Landline
312-377
Wood Dale
Xo Illinois Inc.
Landline
312-378
Hinsdale
Usa Mobility Wireless Inc.
Wireless
312-379
Chicago
Ovation Communications Of Illinois Inc.
Landline
312-380
Chicago
Ameritech Illinois
Landline
312-381
Chicago
Ameritech Illinois
Landline
312-382
Chicago
Ameritech Illinois
Landline
312-384
Chicago
Ameritech Illinois
Landline
312-385
Chicago
Ameritech Illinois
Landline
312-386
Chicago
Ameritech Illinois
Landline
312-387
Hinsdale
Usa Mobility Wireless Inc.
Wireless
312-388
Lombard
United States Cellular Corp. - Illinois
Wireless
312-389
Hinsdale
Usa Mobility Wireless Inc.
Wireless
312-390
Chicago
American Messaging (am) Inc.
Landline
312-391
Willowbrook
New Cingular Wireless Pcs Llc - Il
Wireless
312-393
Chicago
American Messaging (am) Inc.
Landline
312-394
Chicago
Ameritech Illinois
Landline
312-395
Chicago
At&t Local
Landline
312-396
Chicago
Ameritech Illinois
Landline
312-397
Chicago
Ameritech Illinois
Landline
312-398
Hinsdale
Usa Mobility Wireless Inc.
Wireless
312-399
Bridgeview
Sprint Spectrum L.p.
Wireless
312-400
Chicago
American Messaging (am) Inc.
Landline
312-401
Willowbrook
New Cingular Wireless Pcs Llc - Il
Wireless
312-402
Willowbrook
New Cingular Wireless Pcs Llc - Il
Wireless
312-403
Hickory Hills
Cellco Partnership Dba Verizon Wireless - Il
Wireless
312-404
Chicago
T-mobile Usa Inc.
Wireless
312-405
Elgin
Cellco Partnership Dba Verizon Wireless - Il
Wireless
312-406
Schaumburg
New Cingular Wireless Pcs Llc - Il
Wireless
312-407
Chicago
Ameritech Illinois
Landline
312-408
Chicago
Ameritech Illinois
Landline
312-409
Chicago
Ameritech Illinois
Landline
312-410
Chicago
Ameritech Illinois
Landline
312-412
Schaumburg
New Cingular Wireless Pcs Llc - Il
Wireless

Top prefixes in this area code

312-201→312-202→312-203→312-204→312-205→312-206→312-207→312-208→
Why area code pages matter in reverse phone lookup

Area code pages help visitors understand the wider calling region connected to a number. While a full reverse phone lookup page focuses on one specific caller, an area code page shows the bigger picture by grouping prefixes, cities, and carrier patterns under the same first three digits. This makes it easier to spot whether a number appears local, regional, or part of a service area the visitor already recognizes.

For phone directory websites, area code pages also improve browsing. A user can start with a missed call, discover the number's first three digits, and then move into the related area code to see supporting location data and a list of active prefixes. That layered navigation creates a better research experience and gives visitors more confidence when they continue into a specific number page.