Illinois, is a state of the United States of America. Illinois is the 21st state of the USA constituted in 1818. Springfield is the capital city of Illinois.
Where in the United States is Illinois? Location map of Illinois in the US.
Illinois is divided into 102 counties.
|Joined The Union:||December 3, 1818|
Area Codes in Illinois - Below are all the area codes in Illinois. Clicking on an area code will show the cities in that area code.Illinois has area codes of 217, 224, 309, 312, 331, 618, 630, 708, 773, 779, 815, 847, 872.