A 312 reads downtown Chicago
Restricted to the Loop and surrounding core, 312 is the prefix Chicago agencies, traders and law firms recognise as "downtown insider."
Get a 312 Chicago, 773 city-wide, 847 north suburbs, 217 Springfield or any of Illinois's 14 area codes on the phone you already own. The Land of Lincoln's full prefix map — pick the code your customers will recognise on caller ID.
Illinois has 15 active area codes — 312, 773, 872 and 12 more. You can get a virtual Illinois phone number from any of these area codes through CallMama without a US address or SIM card.
Illinois received four original area codes in 1947: 312 (Chicago), 815 (Rockford and northern Illinois), 217 (Springfield and central IL) and 618 (southern Illinois). 309 was added in 1957 to serve the Peoria area. Chicago alone has carried 312 since day one.
The 1989 split moved suburban Cook County out of 312 to a new 708 code. In 1996, Chicago's 773 was carved out for the city outside the Loop, leaving 312 confined to downtown. The same year, 630 split from 708 for the western suburbs and 847 for the northern ones.
Overlays followed as Chicagoland's cellular density grew: 872 (2009) over Chicago, 224 (2002) over 847, 331 (2007) over 630, 779 (2007) over 815. Downstate Illinois added 447 (2024) over 217 and 730 (2025) over 618 to keep pace with cellular number demand.
Chicago's 312 is the most narrowly-restricted major US area code — confined to the Loop and immediately surrounding downtown since the 1996 split moved 773 to the rest of the city. Along with Manhattan's 212, SF's 415 and Boston's 617, 312 is one of only a few US codes restricted to a city's core, and the smallest geographic coverage of the four.
Every Illinois area code plotted at its primary city. Click any marker for that code's details. Overlays share geography with their parent code — they're shown offset on the map for visibility.
Every Illinois metro covered by a different prefix. Open any card to view its full detail page.
Find your city, find its area code, then activate a number with that prefix.
A local Illinois prefix outperforms an out-of-state cell at every customer touchpoint.
Restricted to the Loop and surrounding core, 312 is the prefix Chicago agencies, traders and law firms recognise as "downtown insider."
In Lincoln Park, Wicker Park, Pilsen and Hyde Park, a 773 reads as "real Chicagoan" — distinct from 312 (downtown) and the suburban 847/630.
Serving 312 downtown, 773 city and 847 north shore from the same business? Add three lines on one CallMama account, each routing separately.
A 312 or 217 prefix tells St. Louis, Minneapolis and Indianapolis clients you're on their schedule — no awkward time math from a coastal cell.
NANPA-routed Illinois numbers pass carrier authentication, so cold-call recipients see your local prefix rather than a flagged spam tag.
Cancel service and your Illinois number is reserved free for 12 months — no re-port fees, no losing the 312 you fought to claim.
Each Illinois area code covers a distinct region. Here's how the population breaks down.
Source: US Census Bureau / ACS estimates.
Pick the digits, install the app, take the first call. That's the whole sequence.
CallMama generates 10–20 available numbers in any Illinois area code. Vanity patterns supported.
Install CallMama on the device you already use. Sign in once — your Illinois number is linked.
Inbound and outbound on the same device. Local Illinois caller ID on every outgoing call.
Search by state, city, or number — then click any code to open its detail page. Illinois is in here too.
| State | Area Codes | Time Zone | Count |
|---|---|---|---|
| Alabama | 205251256334659938 | CT | 6 |
| Alaska | 907 | AKT | 1 |
| Arizona | 480520602623928 | MST | 5 |
| Arkansas | 479501870 | CT | 3 |
| California | 213310408415510619650714818916 | PT | 10 |
| Colorado | 303719720970 | MT | 4 |
| Connecticut | 203475860959 | ET | 4 |
| Delaware | 302 | ET | 1 |
| District of Columbia | 202 | ET | 1 |
| Florida | 239305321407561727786813850904954 | ET* | 11 |
| Georgia | 229404470478678706762770912 | ET | 9 |
| Hawaii | 808 | HST | 1 |
| Idaho | 208986 | MT* | 2 |
| Illinois | 217224309312331618630708773779815847872 | CT | 13 |
| Indiana | 219260317463574765812930 | ET* | 8 |
| Iowa | 319515563641712 | CT | 5 |
| Kansas | 316620785913 | CT* | 4 |
| Kentucky | 270364502606859 | ET* | 5 |
| Louisiana | 225318337504985 | CT | 5 |
| Maine | 207 | ET | 1 |
| Maryland | 240301410443667 | ET | 5 |
| Massachusetts | 339351413508617774781857978 | ET | 9 |
| Michigan | 231248269313517586616734810906947989 | ET* | 12 |
| Minnesota | 218320507612651763952 | CT | 7 |
| Mississippi | 228601662769 | CT | 4 |
| Missouri | 314417573636660816 | CT | 6 |
| Montana | 406 | MT | 1 |
| Nebraska | 308402531 | CT* | 3 |
| Nevada | 702725775 | PT | 3 |
| New Hampshire | 603 | ET | 1 |
| New Jersey | 201551609732848856862908973 | ET | 9 |
| New Mexico | 505575 | MT | 2 |
| New York | 212315332347516518585607631646680716718838845914917929934 | ET | 19 |
| North Carolina | 252336704743828910919980984 | ET | 9 |
| North Dakota | 701 | CT* | 1 |
| Ohio | 216234330380419440513567614740937 | ET | 11 |
| Oklahoma | 405539580918 | CT | 4 |
| Oregon | 458503541971 | PT* | 4 |
| Pennsylvania | 215267272412445484570610717724814878 | ET | 12 |
| Rhode Island | 401 | ET | 1 |
| South Carolina | 803843854864 | ET | 4 |
| South Dakota | 605 | CT* | 1 |
| Tennessee | 423615629731865901931 | CT* | 7 |
| Texas | 210214254281325346361409430432469512682713737806817830832903 | CT* | 20 |
| Utah | 385435801 | MT | 3 |
| Vermont | 802 | ET | 1 |
| Virginia | 276434540571703757804 | ET | 7 |
| Washington | 206253360425509564 | PT | 6 |
| West Virginia | 304681 | ET | 2 |
| Wisconsin | 262414534608715920 | CT | 6 |
| Wyoming | 307 | MT | 1 |
| Puerto Rico | 787939 | AST | 2 |
One tap to install. One more to call. It really is that simple.