Illinois | State Facts & History - Infoplease
https://www.infoplease.com/us/states/illinois
WebNov 30, 2023 · Official Name: State of Illinois. Organized as a territory/republic: February 3, 1809. Entered Union (21): December 3, 1818 (21st state) Present constitution adopted: 1970. State abbreviation/Postal code: Ill./IL. State Area Codes: 217, 224, 309, 312, 331, 618, 630, 708, 773, 779, 815, 847 and 872. Fun Facts About Illinois.
DA: 16 PA: 16 MOZ Rank: 20