DeKalb, IL Area Codes
DeKalb, Illinois (population 40,467) uses area codes 815 and 779.
Carriers with DeKalb numbers
39 prefixes are assigned to the DeKalb exchange: 36% mobile, 26% VoIP and cable, 38% landline.
| Carrier | Prefixes |
|---|---|
| Frontier | 7 |
| UScellular | 4 |
| T-Mobile | 4 |
| Verizon Wireless | 4 |
| Onvoy (Sinch) | 3 |
| AT&T Mobility | 2 |
| Verizon Business (MCImetro) | 2 |
| Lumen (Level 3) | 2 |
Area codes used in DeKalb
| Area code | Prefixes serving DeKalb | Main carriers in this code |
|---|---|---|
| 815 | 24 | Frontier, AT&T (Illinois Bell), Lumen (Level 3) |
| 779 | 15 | Onvoy (Sinch), AT&T Mobility, Stratus Networks |
DeKalb phone number prefixes
Numbers starting with these first six digits were originally assigned to the DeKalb exchange.
815-217Digital Network Access Communications815-375UScellular815-501Metropcs815-508AT&T Mobility815-517Verizon Business (MCImetro)815-593T-Mobile815-748Frontier815-751Verizon Wireless815-752Frontier815-753Frontier815-754Frontier815-756Frontier815-757UScellular815-758Frontier815-761Verizon Wireless815-762Verizon Wireless815-764UScellular815-766UScellular815-787Frontier815-793T-Mobile815-901Comcast (Xfinity)815-909T-Mobile815-981Lumen (Level 3)815-995AT&T (Teleport)779-212Nuso779-217Boost Subscriberco L.L.C.779-255Onvoy (Sinch)779-270Verizon Business (MCImetro)779-276Stratus Networks779-334Lumen (Level 3)779-365Nuso779-400magicJack (YMax)779-422Verizon Wireless779-431T-Mobile779-446At&T Enterprises779-775Skyetel779-777AT&T Mobility779-902Onvoy (Sinch)779-910Onvoy (Sinch)
Nearby cities in area code 815
- Joliet
- Rockford
- Plainfield
- Crystal Lake
- McHenry
- New Lenox
- Lockport
- Woodstock
- Belvidere
- Homer Glen
- Loves Park
- Kankakee
Questions
- What is the area code for DeKalb, IL?
- DeKalb uses 2 area codes: 815 and 779. They overlay each other, so all of them cover the whole city and you dial 10 digits for local calls.
- What time zone is DeKalb in?
- DeKalb is in the Central time zone.