The Investigator’s Guide to Area Codes: Locating Leads and Identifying Red Flags

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A map showing area codes

A telephone number is often the very first clue in a new investigation. For private investigators and law enforcement, those ten digits hold a wealth of potential information. The first three digits, the area code, used to be a definitive indicator of a person’s geographic location. Today, it is more complicated, but it remains a vital data point.

Understanding the structure of the North American Numbering Plan (NANP) is essential for effective skip tracing, background checks, and analyzing call detail records. This article delves into what investigators need to know about the modern telephone landscape. We also provide complete reference tables for area codes across the United States.

The North American Numbering Plan (NANP) Explained

The NANP is the system that governs telephone numbers in twenty countries. This includes the United States and its territories, Canada, and several Caribbean nations. The system was created by AT&T in the 1940s to simplify long-distance dialing.

Before this system, connections often required an operator. The NANP standardized numbering, allowing for direct dialing across the continent. Today, there are hundreds of active area codes within this system, accommodating billions of phone numbers.

The Complexity of Modern Area Codes

Sixty years ago, if a subject had a “212” area code, you knew they were in New York City. Today, that assumption can lead an investigator down the wrong path. The explosion in demand for telephone numbers, driven by mobile phones and internet devices, changed everything.

The Rise of Overlays

When a geographic region runs out of available phone numbers, the NANP administrator doesn’t just split the region in half anymore. Instead, they usually implement an “overlay.”

An overlay adds a new area code to the exact same geographic territory as an existing one. This means your subject and their next-door neighbor could have completely different area codes. It also mandates 10-digit dialing for local calls within that region.

For investigators, this means an area code still indicates a general region, but it is less specific than before. You must verify the subscriber’s actual location through other means, such as utility data or credit header information.

Number Portability

Another factor complicating geographic location is Local Number Portability (LNP). This Federal Communications Commission (FCC) rule allows consumers to keep their phone numbers when switching service providers.

A person might originally obtain a mobile number in California but keep it after moving to Florida. The area code remains “310,” but the user is thousands of miles away. A skilled private investigator always cross-references phone data with current address records.

Investigative Red Flags: VoIP and Scams

Modern technology has created new tools for criminals to hide their identity. Understanding how area codes interact with these technologies is crucial for spotting deception.

Voice over IP (VoIP) and Virtual Numbers

VoIP services transmit calls over the internet rather than traditional phone lines. These services allow users to choose virtually any area code they want, regardless of their physical location.

A subject using a VoIP number could pick a local area code to appear trustworthy to their victims. Investigators should use carrier lookup tools to determine if a number belongs to a VoIP provider. A VoIP number is often a red flag indicating the user may not be where they claim to be.

The “One Ring” Scam and International Codes

Scammers often use phone numbers that appear domestic but are actually international. They rely on victims not recognizing the area code.

For example, area code “876” looks like a standard US code, but it connects to Jamaica. If a target returns a missed call to this number, they may be charged enormous international rates. Investigators need to recognize these “look-alike” codes to protect clients and identify fraudulent schemes.

Using Area Code Lists in Investigations

Despite the complexities of modern telephony, area code lists are still essential reference tools. They are vital for quickly identifying the originating region of a phone number found during discovery.

When analyzing Call Detail Records (CDRs), investigators use these lists to map out a subject’s contacts. Seeing clusters of calls to a specific geographic region can reveal hidden relationships or unknown locations.

Below are two comprehensive tables. The first lists area codes alphabetically by state. The second lists the same data numerically for quick lookup.

  • Suggested Internal Link: Learn more about how phone data aids in locating missing persons on our Skip Tracing page.
  • Suggested External Link: For official data on numbering resources, visit the North American Numbering Plan Administrator (NANPA) website.

Table 1: Area Codes Listed by State

This table helps you determine which state a specific area code belongs to.

State / RegionArea Codes
Alabama205, 251, 256, 334, 659, 938
Alaska907
Arizona480, 520, 602, 623, 928
Arkansas479, 501, 870
California209, 213, 279, 310, 323, 408, 415, 424, 442, 510, 530, 559, 562, 619, 626, 628, 650, 657, 661, 669, 707, 714, 747, 760, 805, 818, 820, 831, 858, 909, 916, 925, 949, 951
Colorado303, 719, 720, 970, 983
Connecticut203, 475, 860, 959
Delaware302
District of Columbia202, 771
Florida239, 305, 321, 352, 386, 407, 561, 689, 727, 754, 772, 786, 813, 850, 863, 904, 941, 954
Georgia229, 404, 470, 478, 678, 706, 762, 770, 912
Hawaii808
Idaho208, 986
Illinois217, 224, 309, 312, 331, 618, 630, 708, 773, 779, 815, 847, 872
Indiana219, 260, 317, 463, 574, 765, 812, 930
Iowa319, 515, 563, 641, 712
Kansas316, 620, 785, 913
Kentucky270, 364, 502, 606, 859
Louisiana225, 318, 337, 504, 985
Maine207
Maryland240, 301, 410, 443, 667
Massachusetts339, 351, 413, 508, 617, 774, 781, 857, 978
Michigan231, 248, 269, 313, 517, 586, 616, 734, 810, 906, 947, 989
Minnesota218, 320, 507, 612, 651, 763, 952
Mississippi228, 601, 662, 769
Missouri314, 417, 557, 573, 636, 660, 816
Montana406
Nebraska308, 402, 531
Nevada702, 725, 775
New Hampshire603
New Jersey201, 551, 609, 732, 848, 856, 862, 908, 973
New Mexico505, 575
New York212, 315, 332, 347, 516, 518, 585, 607, 631, 646, 680, 716, 718, 838, 845, 914, 917, 929, 934
North Carolina252, 336, 704, 743, 828, 910, 919, 980, 984
North Dakota701
Ohio216, 234, 326, 330, 419, 440, 513, 567, 614, 740, 937
Oklahoma405, 539, 580, 918
Oregon458, 503, 541, 971
Pennsylvania215, 223, 267, 272, 412, 484, 570, 610, 717, 724, 814, 878
Rhode Island401
South Carolina803, 843, 854, 864
South Dakota605
Tennessee423, 615, 629, 731, 865, 901, 931
Texas210, 214, 254, 281, 325, 346, 361, 409, 430, 432, 469, 512, 682, 713, 726, 737, 806, 817, 830, 903, 915, 936, 940, 956, 972, 979
Utah385, 435, 801
Vermont802
Virginia276, 434, 540, 571, 703, 757, 804
Washington206, 253, 360, 425, 509, 564
West Virginia304, 681
Wisconsin262, 414, 534, 608, 715, 920
Wyoming307

Table 2: Area Codes in Numerical Order

This table is useful when you have an area code and need to identify its originating state quickly.

Area Code – StateArea Code – StateArea Code – StateArea Code – State
201 – NJ202 – DC203 – CT205 – AL
206 – WA207 – ME208 – ID209 – CA
210 – TX212 – NY213 – CA214 – TX
215 – PA216 – OH217 – IL218 – MN
219 – IN223 – PA224 – IL225 – LA
228 – MS229 – GA231 – MI234 – OH
239 – FL240 – MD248 – MI251 – AL
252 – NC253 – WA254 – TX256 – AL
260 – IN262 – WI267 – PA269 – MI
270 – KY272 – PA276 – VA279 – CA
281 – TX301 – MD302 – DE303 – CO
304 – WV305 – FL307 – WY308 – NE
309 – IL310 – CA312 – IL313 – MI
314 – MO315 – NY316 – KS317 – IN
318 – LA319 – IA320 – MN321 – FL
323 – CA325 – TX326 – OH330 – OH
331 – IL332 – NY334 – AL336 – NC
337 – LA339 – MA346 – TX347 – NY
351 – MA352 – FL360 – WA361 – TX
364 – KY385 – UT386 – FL401 – RI
402 – NE404 – GA405 – OK406 – MT
407 – FL408 – CA409 – TX410 – MD
412 – PA413 – MA414 – WI415 – CA
417 – MO419 – OH423 – TN424 – CA
425 – WA430 – TX432 – TX434 – VA
435 – UT440 – OH442 – CA443 – MD
458 – OR463 – IN469 – TX470 – GA
475 – CT478 – GA479 – AR480 – AZ
484 – PA501 – AR502 – KY503 – OR
504 – LA1505 – NM2507 – MN3508 – MA4
509 – WA5510 – CA6512 – TX7513 – OH8
515 – IA9516 – NY10517 – MI11518 – NY12
520 – AZ13530 – CA14531 – NE15534 – WI16
539 – OK17540 – VA18541 – OR19551 – NJ20
557 – MO21559 – CA22561 – FL23562 – CA24
563 – IA25564 – WA26567 – OH27570 – PA28
571 – VA29573 – MO30574 – IN31575 – NM32
580 – OK33585 – NY34586 – MI35601 – MS36
602 – AZ37603 – NH38605 – SD39606 – KY40
607 – NY41608 – WI42609 – NJ43610 – PA44
612 – MN45614 – OH46615 – TN47616 – MI48
617 – MA49618 – IL50619 – CA51620 – KS52
623 – AZ53626 – CA54628 – CA55629 – TN56
630 – IL57631 – NY58636 – MO59641 – 60IA
646 – NY650 – CA651 – MN657 – CA
659 – AL660 – MO661 – CA662 – MS
667 – MD669 – CA678 – GA680 – NY
681 – WV682 – TX689 – FL701 – ND
702 – NV703 – VA704 – NC706 – GA
707 – CA708 – IL712 – IA713 – TX
714 – CA715 – WI716 – NY717 – PA
718 – NY719 – CO720 – CO724 – PA
725 – NV726 – TX727 – FL731 – TN
732 – NJ734 – MI737 – TX740 – OH61
743 – NC62747 – CA63754 – FL64757 – VA65
760 – CA66762 – GA67763 – MN68765 – IN69
769 – MS70770 – GA71771 – DC72772 – FL73
773 – IL74774 – MA75775 – NV76779 – IL77
781 – MA78785 – KS79786 – FL80801 – UT81
802 – VT82803 – SC83804 – VA84805 – CA85
88606 – TX808 – HI810 – MI812 – IN
813 – FL814 – PA815 – IL816 – MO
817 – TX818 – CA820 – CA828 – NC
830 – TX831 – CA838 – NY843 – SC
845 – NY847 – IL848 – NJ850 – FL
854 – SC856 – NJ857 – MA858 – CA
859 – KY860 – CT862 – NJ863 – FL
864 – SC865 – TN870 – AR872 – IL
878 – PA901 – TN903 – TX904 – FL
906 – MI907 – AK908 – NJ909 – CA
910 – NC912 – GA913 – KS914 – NY
915 – TX916 – CA917 – NY918 – OK
919 – NC920 – WI925 – CA928 – AZ
929 – NY930 – IN931 – TN934 – NY
936 – TX937 – OH938 – AL940 – TX
941 – FL947 – MI949 – CA951 – CA
952 – MN954 – FL956 – TX959 – CT
970 – CO971 – OR972 – TX973 – NJ
978 – MA979 – TX980 – NC983 – CO
984 – NC985 – LA986 – ID989 – MI

Sources:

  • https://www.fcc.gov/consumers/guides/porting-keeping-your-phone-number-when-you-change-providers
    • Michael Kissiah
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