Area code 815 is a telephone area code for the northwestern corner and southern Chicago suburbs of the state of Illinois. An overlay area code 779 was implemented on March 17 of 2007. A month earlier, on February 17, 1+ten-digits were required to be dialed for all calls in and out of area code 815--in preparation for the 779 overlay. The telephone is a telecommunications device which is used to transmit and receive sound (most commonly speech) across distance. ... A telephone numbering plan is a system that allows subscribers to make and receive telephone calls across long distances. ... Nickname: Motto: Urbs In Horto (Latin: City in a Garden), I Will Location in Chicagoland and Illinois Coordinates: Country United States State Illinois County Cook & DuPage Incorporated March 4, 1837 Government  - Mayor Richard M. Daley (D) Area  - City  234. ... Official language(s) English[1] Capital Springfield Largest city Chicago Largest metro area Chicago Area  Ranked 25th  - Total 57,918 sq mi (149,998 km²)  - Width 210 miles (340 km)  - Length 390 miles (629 km)  - % water 4. ...

Cities in the 815/779 area code include:
Apple River, Illinois
Belvidere, Illinois
Bolingbrook, Illinois
Byron, Illinois--Prefixes include: 234 406 803
Cortland, Illinois
Cedarville, Illinois--Prefixes include: 563
Coal City, Illinois
Crystal Lake, Illinois--Prefixes include: 204 219 261 276 301 356 404 425 444 455 459 477 479 526 788 893
Davis Junction, Illinois--Prefixes include:
DeKalb, Illinois--Prefixes include: 748 753 756 758
Dixon, Illinois
East Dubuque, Illinois
Frankfort, Illinois--Prefixes include: 464 469 806
Freeport, Illinois--Prefixes include: 232 233 235 238 266 275 291 297 541 599 616 618 650 656 801 821 908 990
Galena, Illinois
Joliet, Illinois--Prefixes include: 720 725 727 729 730 741 744
Kankakee, Illinois
Lanark, Illinois--Prefixes include: 270 493 658 952
La Salle, Illinois--Prefixes include: 220 223 224
Lena, Illinois--Prefixes include: 369 809
Loves Park, Illinois
Machesney Park, Illinois
Malta, Illinois
McHenry, Illinois
Mendota, Illinois
Minooka, Illinois
Mokena, Illinois--Prefixes include: 479
Monroe Center, Illinois--Prefixes include: 393
Morris, Illinois
Mount Morris, Illinois--Prefixes include: 734
New Lenox, Illinois--Prefixes include: 485 462 463 919 212
Orangeville, Illinois--Prefixes include: 789 819
Oregon, Illinois--Prefixes include: 732
Ottawa, Illinois
Plainfield, Illinois
Princeton, Illinois--Prefixes include: 872 875 876 879
Rochelle, Illinois--Prefixes include: 561 562 888 917
Rockford, Illinois--Prefixed include: 201 202 209 218 222 226 227 229 231 242 243 262 282 289 296 298 299 315 316 319 378 381 387 391 394 395 397 398 399 470 480 484 489 490 494 505 509 516 519 520 540 543 558 601 608 621 633 636 637 639 641 654 670 681 703 708 713 720 721 742 749 763 847 860 870 871 877 904 914 921 961 962 963 964 965 966 967 968 969 971 972 977 978 979 980 983 985 986 987 988 997
Romeoville, Illinois
Savanna, Illinois
Shannon, Illinois
Spring Valley, Illinois--Prefixes include: 663 664
Sterling, Illinois
Stillman Valley, Illinois--Prefixes include: 645
Stockton, Illinois--Prefixes include: 840 947
Streator, Illinois
Sycamore, Illinois--Prefixes include: 895 889
Tinley Park, Illinois
Warren, Illinois--Prefixes include: 745 818
Woodstock, Illinois

The 608 area code currently covers much of southwestern Wisconsin, including the capital city of Madison as well as the cities of Baraboo, Beloit, Janesville, La Crosse, and Platteville. ... The 262 area code currently covers much of the suburbs of Milwaukee, Wisconsin, but not Milwaukee County itself. ... Area Code 563 is a telephone area code for a portion the state of Iowa, specifically the east central and northeast corner of the state. ... Both area code 847 and area code 224 are part of an overlay plan that covers most of Lake County, the northern part of Cook County, the northern part of Kane County, and a small part of McHenry County in Illinois. ... In the United States telephone system, Area code 630 covers the entirety of Dupage County in Illinois. ... Area code 708 covers western and southern Cook County and eastern and southern Will County in Illinois. ... Area code 309 is the telephone area code serving the state of Illinois. ... The 217 area code currently covers much of Central Illinois, including the capital city of Springfield as well as the cities of Champaign, Urbana, Decatur, Danville, Quincy, and Rantoul. ... Apple River is a village located in Jo Daviess County, Illinois. ... Belvidere is a city in Boone County, Illinois, United States. ... Incorporated Village in 1965. ... Byron is a city in Ogle County, Illinois, United States. ... Cortland is a town located in DeKalb County, Illinois. ... Cedarville is a village located in Stephenson County, Illinois. ... Coal City is a village in Grundy County, Illinois, United States. ... Crystal Lake is a city located in southeastern McHenry County in northeastern Illinois. ... Davis Junction is a village in Ogle County, Illinois. ... DeKalb is a city located in DeKalb County, Illinois. ... Dixon is a city located in Lee County, Illinois, USA. It is the county seat of Lee CountyGR6. ... East Dubuque is a city located in Jo Daviess County, Illinois. ... Incorporated Village in 1879. ... Lincoln-Douglas debates monument, near downtown Freeport. ... Coordinates: Country United States State Illinois Counties Jo Daviess Mayor Tom F. Brusch Area    - City 9. ... Incorporated City in 1834. ... Kankakee is a city in Kankakee County, Illinois, in the United States. ... Lanark is a city located in Carroll County, Illinois. ... The city of La Salle is located in LaSalle County, Ill. ... Lena is a village located in Stephenson County, Illinois. ... Loves Park is a city in Winnebago County, Illinois, United States. ... Machesney Park is a suburb of Rockford Illinois located in Winnebago County, Illinois, United States. ... Malta is a village located in DeKalb County, Illinois. ... McHenry is a city in McHenry County, Illinois, United States. ... Mendota is a city located in La Salle County, Illinois. ... Chicago, Ottawa and Peoria Railway, Illinois Traction System, Minooka Passenger Station. ... Mokena is a village located in Will County, Illinois. ... Monroe Center is a village in Ogle County, Illinois, is located southeast of Rockford. ... Morris is a city located in Grundy County, Illinois. ... Mount Morris is a village located in Ogle County, Illinois. ... New Lenox is a village located in Will County, Illinois. ... Orangeville is a village located in Stephenson County, Illinois. ... Oregon is a city located in Ogle County, Illinois. ... Ottawa is a city in north-central Illinois. ... The Village of Plainfield is a municipality located in Will County, Illinois. ... Princeton is a city located in Bureau County, Illinois. ... Rochelle is a city located in Ogle County, Illinois. ... This article does not cite any references or sources. ... Romeoville is a village in Will County, Illinois, United States. ... Savanna is a city in Carroll County, Illinois, United States. ... Shannon is a village located in Carroll County, Illinois. ... Spring Valley is a city situated on the Illinois River in Bureau County, Illinois. ... Sterling is a city located in Whiteside County, Illinois. ... Stillman Valley is a village located in Ogle County, Illinois. ... Stockton is a village located in Jo Daviess County, Illinois. ... Streator is a city located in La Salle County, Illinois in the midwestern United States. ... Sycamore is a city in DeKalb County, Illinois, United States. ... Incorporated Village in 1892. ... Warren is a village located in Jo Daviess County, Illinois. ... Northwest corner of Woodstocks public square // Woodstock is a city in McHenry County, Illinois, United States. ...

	Illinois Area codes 217 | 224 | 309 | 312 | 618 | 630 | 708 | 773 | 779 | 815 | 847