National Phone Number Registry NPNR

Area Code 312 Location

Area code 312 is currently assigned for use in Illinois since Jan 01, 1947. View all phone prefixes used in area code 312 or other area codes in Illinois.

(312)
Enter 7-digit phone number for area code 312 or the complete 10-digit phone number

Phone Prefixes for Area Code 312

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Area code Location Company / Service Provider
312-201 CHICAGO, IL AMERITECH ILLINOIS
312-202 CHICAGO, IL AMERITECH ILLINOIS
312-203 CHICAGO, IL NEW CINGULAR WIRELESS PCS, LLC - IL
312-204 CHICAGO, IL AMERITECH ILLINOIS
312-205 CHICAGO, IL ALLEGIANCE TELECOM, INC. - IL
312-206 CHICAGO, IL NEW CINGULAR WIRELESS PCS, LLC - IL
312-207 CHICAGO, IL AMERITECH ILLINOIS
312-208 CHICAGO, IL NEW CINGULAR WIRELESS PCS, LLC - IL
312-209 NORTHBROOK, IL CELLCO PARTNERSHIP DBA VERIZON WIRELESS - IL
312-212 CHICAGO, IL AMERITECH ILLINOIS
312-213 CHICAGO, IL NEW CINGULAR WIRELESS PCS, LLC - IL
312-214 CHICAGO, IL AMERITECH ILLINOIS
312-215 WHEELING, IL NEW CINGULAR WIRELESS PCS, LLC - IL
312-216 CHICAGO, IL FIRST COMMUNICATIONS LLC - IL
312-217 CHICAGO, IL SPRINT SPECTRUM L.P.
312-218 CHICAGO, IL NEW CINGULAR WIRELESS PCS, LLC - IL
312-219 CHICAGO, IL BANDWIDTH.COM CLEC, LLC - IL
312-220 CHICAGO, IL AMERITECH ILLINOIS
312-221 CHICAGO, IL SPRINT SPECTRUM L.P.
312-222 CHICAGO, IL AMERITECH ILLINOIS
312-223 CHICAGO, IL AMERITECH ILLINOIS
312-224 CHICAGO, IL BROADWING COMMUNICATIONS, LLC - IL
312-225 CHICAGO, IL AMERITECH ILLINOIS
312-226 CHICAGO, IL AMERITECH ILLINOIS
312-227 CHICAGO, IL AMERITECH ILLINOIS
312-228 CHICAGO, IL AMERITECH ILLINOIS
312-229 CHICAGO, IL AMERITECH ILLINOIS
312-230 CHICAGO, IL AMERITECH ILLINOIS
312-231 ROSELLE, IL NEW CINGULAR WIRELESS PCS, LLC - IL
312-232 CHICAGO, IL AMERICAN MESSAGING SERVICES, LLC
312-233 CHICAGO, IL AMERITECH ILLINOIS
312-234 CHICAGO, IL AMERITECH ILLINOIS
312-235 CHICAGO, IL AMERITECH ILLINOIS
312-236 CHICAGO, IL AMERITECH ILLINOIS
312-237 CHICAGO, IL CELLCO PARTNERSHIP DBA VERIZON WIRELESS - IL
312-238 CHICAGO, IL BROADWING COMMUNICATIONS, LLC - IL
312-239 CHICAGO, IL AT&T LOCAL
312-240 CHICAGO, IL AMERITECH ILLINOIS
312-241 CHICAGO, IL NEW CINGULAR WIRELESS PCS, LLC - IL
312-242 CHICAGO, IL TELEPORT COMMUNICATIONS AMERICA, LLC - IL
312-243 CHICAGO, IL AMERITECH ILLINOIS
312-244 CHICAGO, IL AMERITECH ILLINOIS
312-245 CHICAGO, IL AMERITECH ILLINOIS
312-246 WHEELING, IL NEW CINGULAR WIRELESS PCS, LLC - IL
312-247 CHICAGO, IL FIRST COMMUNICATIONS LLC - IL
312-248 CHICAGO, IL METRO PCS, INC.
312-249 CHICAGO, IL USA MOBILITY WIRELESS, INC.
312-250 CHICAGO, IL USA MOBILITY WIRELESS, INC.
312-251 CHICAGO, IL AMERITECH ILLINOIS
312-252 CHICAGO, IL ALLEGIANCE TELECOM, INC. - IL
312 Area Code Information
Type of code: General Purpose Code
Location: IL - US
Time zone: C
Assigned for use: Yes
Code in service: Yes
Service date: January 01, 1947
In jeopardy: No
Relief in progress: Yes
NPA Relief status: Active
Code assignable: Yes
Geographic or
non-geographic:
G
Reserved for future use: No
Planning letter(s): 392 390 195
Overlay code: Yes
Overlay complex: 312/872
Dialing plan Standard Permissive
Home local calls: 1+10D NA
Foreign local calls: 1+10D NA
Home toll calls: 1+10D NA
Foreign toll calls: 1+10D -

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