Area Codes Starting with 3
Includes Chicago (312), Los Angeles Westside (310), Miami (305), Denver (303), and Detroit (313).
All Area Codes in the 300–399 Range
Active geographic numbering plan allocations in the United States.
Area Code 301
Maryland (MD)
Area Code 304
West Virginia (WV)
Area Code 310
California (CA)
Area Code 323
California (CA)
Area Code 336
North Carolina (NC)
Area Code 347
New York (NY)
Data obtained through 3xx area code lookups cannot be used for credit evaluation, employee background checks, tenant screening, or personal insurance eligibility. USA People Search is not a Consumer Reporting Agency.
3xx Area Codes Frequently Asked Questions
Common questions regarding numbering allocations, regional timezones, and caller verification.
What states and regions are served by 3xx area codes?
Area codes starting with digit 3 serve major metropolitan hubs and rural districts across Maryland, Delaware, Colorado, West Virginia, Florida, and other jurisdictions.
How many area codes start with the digit 3?
Currently, there are 24 active North American Numbering Plan area codes assigned within the 300 through 399 numerical range.
Can I perform a reverse phone lookup for any 3xx phone number?
Yes. Enter the 10-digit number into our Reverse Phone Lookup tool to query carrier registries, line types (cellular, landline, VoIP), and subscriber names associated with 3xx prefixes.
Are calls from unfamiliar 3xx area codes safe to answer?
If you do not recognize a caller from a 3xx area code, check the number with a reverse phone lookup first. Robocallers frequently spoof local area codes to trick recipients into answering.
How do timezones work for area codes in the 300–399 range?
Area codes in the 3xx series span various American timezones (Eastern, Central, Mountain, Pacific, Alaska, and Hawaii). Inspect the specific area code listing above to determine its exact local timezone.
Can a cell phone have a 3xx area code even if the person moved?
Yes. Under federal mobile number portability regulations, wireless subscribers retain their original area codes even after relocating permanently across state lines.
What is the difference between landline and mobile numbers in 3xx area codes?
Landlines are tied to physical street addresses via copper or fiber, whereas cellular numbers are assigned to wireless SIMs. Reverse lookups identify line type and registered billing location.
Can telemarketers spoof 3xx area codes?
Yes. Malicious callers utilize VoIP dialers to spoof caller ID displays. A reverse lookup checks active carrier allocations to reveal if a number is an active wireless subscriber or virtual line.
Can I use records retrieved from 3xx phone lookups for background checks?
No. Reverse phone lookups are not consumer reports under the Fair Credit Reporting Act (15 U.S.C. § 1681) and cannot be used for tenant screening, hiring decisions, or credit evaluation.
How can a phone subscriber with a 3xx area code opt out of directories?
Subscribers can remove their records by submitting an opt-out request through Spokeo's removal page (spokeo.com/optout) or following our comprehensive Opt-Out guide.
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USA People Search does not own, manage, or operate an internal background check database. All searches initiated on this site are securely redirected to our third-party partner, Spokeo, which provides the underlying public records search services. We may receive referral fees when you choose to use partner services, which supports our ongoing directory research.