A Map of the U.S. state Illinois

Illinois Facts

  • U.S. State: Illinois
  • Abbreviation: IL
  • Joined the USA: December 3rd, 1818 (21st State)
  • Located: Midwestern United States
  • Capital City: Springfield, IL
  • Most Populated City: Chicago, IL

34 Illinois Facts for Kids

  1. Illinois is a state in the United States of America.
  2. Illinois is in the midwestern region of the United States.
  3. Illinois became a U.S. state on Thursday, December 3rd, 1818.
  4. Illinois was the 21st state to join the United States.
  5. The U.S. state of Illinois covers 57,915 square miles.
  6. Illinois is the 25th largest state by area in the United States.
  7. In 2019, the population of Illinois was estimated to be 12,670,000 residents by the U.S. Census Bureau.
  8. In 2019, Illinois was the 6th most populated state in the United States.
  9. A person who is from or lives in Illinois is called an Illinoisan.
  10. The capital city of Illinois is Springfield.
  11. The eight most populated cities in Illinois are Chicago, Aurora, Rockford, Juliet, Naperville, Springfield, Peoria and Elgin.
  12. The largest city by population in Illinois is Chicago.
  13. The largest metropolitan area in Illinois is the Chicagoland area.
  14. The U.S. state of Illinois has 102 counties.
  15. The most populated county in Illinois is Cook County with 5,150,000 residents (2019, U.S. Census Bureau).
  16. The largest county by area in Illinois is McLean County with 1,184 square miles.
  17. The highest elevation point in Illinois is Charles Mound at 1,235 feet above sea level
  18. The lowest elevation point in Illinois is the confluence of Mississippi and Ohio River at 280 feet above sea level.
  19. The average precipitation (rain and snow) in Illinois is 38.52 inches.
  20. Illinois is the 30th wettest state by precipitation (rain and snow) in the United States.
  21. The average temperature in Illinois is 51.3 °F.
  22. The warmest temperature ever recorded in Illinois was 117 °F on July 14th, 1954.
  23. The coldest temperature ever recorded in Illinois was -38 °F on January 31st, 2019.
  24. A few natural disasters that can affect Illinois are blizzards, earthquakes, hail, heat waves, ice storms, river flooding, thunderstorms and tornadoes.
  25. Illinois is in one time zone, Central Time Zone (CT).
  26. The USPS abbreviation for Illinois is IL.
  27. The nickname for the U.S. state of Illinois is the “Prairie State”.
  28. Illinois is also known as the “Land of Lincoln”, to honor past U.S. president Abraham Lincoln.
  29. The official state flower of Illinois is the violet (Violaceae).
  30. The official state tree of Illinois is the white oak (Quercus alba).
  31. The official state insect of Illinois is the monarch butterfly (Danaus plexippus)
  32. The official state bird of Illinois is the cardinal (Cardinalidae).
  33. The official state fish of Illinois is the bluegill (Lepomis macrochirus).
  34. The official state animal of Illinois is the white-tailed deer (Odocoileus virginianus).

Additional Resources on Illinois