Area Code 312 is located in the state of Illinois.
The Illinois`s major city is Chicago
The state of Illinois is in Central timezone.
More important cities in Illinois:
Chicago, IL;
Prefixes within the 312 Area Code what we have in our database.
| Prefix | Primary City | County | Usage |
| (312) 308 | Chicago, IL | Cook | Landline |
| (312) 309 | Chicago, IL | Cook | Landline |
| (312) 310 | Northbrook, IL | Cook | Cell Number |
| (312) 313 | Not filled | Cook | Cell Number |
| (312) 314 | Hinsdale, IL | Du Page | Cell Number |
| (312) 315 | Chicago, IL | Cook | Cell Number |
| (312) 316 | Chicago, IL | Cook | Cell Number |
| (312) 317 | Wheeling, IL | Cook | Cell Number |
| (312) 318 | La Grange Park, IL | Cook | Cell Number |
| (312) 320 | Chicago, IL | Cook | Cell Number |
| (312) 321 | Chicago, IL | Cook | Landline |
| (312) 322 | Chicago, IL | Cook | Landline |
| (312) 323 | Chicago, IL | Cook | Cell Number |
| (312) 324 | Chicago, IL | Cook | Landline |
| (312) 325 | Chicago, IL | Cook | Landline |
| (312) 326 | Chicago, IL | Cook | Landline |
| (312) 327 | Chicago, IL | Cook | Landline |
| (312) 328 | Chicago, IL | Cook | Landline |
| (312) 329 | Chicago, IL | Cook | Landline |
| (312) 330 | Chicago, IL | Cook | Cell Number |
| (312) 331 | Wheeling, IL | Cook | Cell Number |
| (312) 332 | Chicago, IL | Cook | Landline |
| (312) 333 | Chicago, IL | Cook | Cell Number |
| (312) 334 | Chicago, IL | Cook | Landline |
| (312) 335 | Chicago, IL | Cook | Landline |
| (312) 336 | Chicago, IL | Cook | Landline |
| (312) 337 | Chicago, IL | Cook | Landline |
| (312) 338 | Chicago, IL | Cook | Landline |
| (312) 339 | Chicago, IL | Cook | Cell Number |
| (312) 341 | Chicago, IL | Cook | Landline |
| (312) 342 | Chicago, IL | Cook | Cell Number |
| (312) 343 | Chicago, IL | Cook | Cell Number |
| (312) 344 | Chicago, IL | Cook | Landline |
| (312) 345 | Chicago, IL | Cook | Landline |
| (312) 346 | Chicago, IL | Cook | Landline |
| (312) 347 | Chicago, IL | Cook | Landline |
| (312) 348 | Chicago, IL | Cook | Landline |
| (312) 349 | Chicago, IL | Cook | Cell Number |
| (312) 350 | Chicago, IL | Cook | Cell Number |
| (312) 351 | Chicago, IL | Cook | Cell Number |
| (312) 352 | Hinsdale, IL | Du Page | Cell Number |
| (312) 353 | Chicago, IL | Cook | Landline |
| (312) 354 | Roselle, IL | Du Page | Cell Number |
| (312) 355 | Chicago, IL | Cook | Landline |
| (312) 356 | Chicago, IL | Cook | Landline |
| (312) 357 | Chicago, IL | Cook | Landline |
| (312) 358 | Not filled | Cook | Cell Number |
| (312) 359 | Chicago, IL | Cook | Cell Number |
| (312) 360 | Chicago, IL | Cook | Landline |
| (312) 361 | Chicago, IL | Cook | Landline |
| (312) 362 | Chicago, IL | Cook | Landline |
| (312) 363 | Chicago, IL | Cook | Landline |
| (312) 364 | Chicago, IL | Cook | Landline |
| (312) 365 | Chicago, IL | Cook | Cell Number |
| (312) 366 | La Grange Park, IL | Cook | Cell Number |
| (312) 367 | La Grange Park, IL | Cook | Cell Number |
| (312) 368 | Chicago, IL | Cook | Landline |
| (312) 369 | Chicago, IL | Cook | Cell Number |
| (312) 370 | Chicago, IL | Cook | Cell Number |
| (312) 371 | Chicago, IL | Cook | Cell Number |
| (312) 372 | Chicago, IL | Cook | Landline |
| (312) 373 | Chicago, IL | Cook | Landline |
| (312) 374 | Chicago, IL | Cook | Landline |
| (312) 375 | Chicago, IL | Cook | Cell Number |
| (312) 376 | Chicago, IL | Cook | Landline |
| (312) 377 | Chicago, IL | Cook | Landline |
| (312) 378 | Chicago, IL | Cook | Cell Number |
| (312) 379 | Chicago, IL | Cook | Landline |
| (312) 380 | Chicago, IL | Cook | Landline |
| (312) 381 | Chicago, IL | Cook | Landline |
| (312) 382 | Chicago, IL | Cook | Landline |
| (312) 383 | Not filled | Cook | Cell Number |
| (312) 384 | Chicago, IL | Cook | Landline |
| (312) 385 | Chicago, IL | Cook | Landline |
| (312) 386 | Chicago, IL | Cook | Landline |
| (312) 387 | Chicago, IL | Cook | Cell Number |
| (312) 388 | Chicago, IL | Cook | Cell Number |
| (312) 389 | Chicago, IL | Cook | Cell Number |
| (312) 390 | Chicago, IL | Cook | Cell Number |
| (312) 391 | Chicago, IL | Cook | Cell Number |
| (312) 393 | Chicago, IL | Cook | Cell Number |
| (312) 394 | Chicago, IL | Cook | Landline |
| (312) 395 | Chicago, IL | Cook | Landline |
| (312) 396 | Chicago, IL | Cook | Landline |
| (312) 397 | Chicago, IL | Cook | Landline |
| (312) 398 | Chicago, IL | Cook | Cell Number |
| (312) 399 | Chicago, IL | Cook | Cell Number |
| (312) 400 | Chicago, IL | Cook | Cell Number |
| (312) 401 | Chicago, IL | Cook | Cell Number |
| (312) 402 | Chicago, IL | Cook | Cell Number |
| (312) 403 | La Grange Park, IL | Cook | Cell Number |
| (312) 404 | Chicago, IL | Cook | Cell Number |
| (312) 405 | Chicago, IL | Cook | Cell Number |
| (312) 406 | Wheeling, IL | Cook | Cell Number |
| (312) 407 | Chicago, IL | Cook | Landline |
| (312) 408 | Chicago, IL | Cook | Landline |
| (312) 409 | Chicago, IL | Cook | Landline |
| (312) 410 | Chicago, IL | Cook | Landline |
| (312) 412 | Wheeling, IL | Cook | Cell Number |
| (312) 413 | Chicago, IL | Cook | Landline |
We have 695 Prefixes in our database.