GENERAL FEATURESIllinois is located in the north-central United States. It is bordered by Wisconsin to the north, Iowa and Missouri to the west, Kentucky to the south and Indiana to the east, and the Wabash and Ohio Rivers on the southeast and south. The landscape of the country can be divided into three major regions: the Central Plains, The Shawnee Hills and the Gulf Coastal Plain.

THE LANDBordered by the Mississippi River on the west and the Wabash and Ohio Rivers on the southeast and south, the landscape of Illinois can be grouped into three main regions; the Central Plains, the Shawnee Hills and the Gulf Coastal Plain.The Central Plains:About 90% of Illinois is covered by the Central Plains region. These gently rolling fertile plains were carved and leveled by glaciers during the Ice Age. The Central Plains run from Lake Michigan west and south to cover most of the state and can be divided into three sections; the Great Lakes Plain, the Driftless Plains and the Till Plains.The Great Lakes Plains:This low flat stretch of land alongLake Michigandevelops some small hills north and west of Chicago.The Driftless Plains:In the northwest corner of Illinois, the Driftless Plains offer the highest elevations in the state. Large hills and valleys are present in this small area of Driftless Plains. This is where Charles Mound, the highest point in Illinois, is located.The Till Plains:By far the largest section of the Central Plains, the Till Plains offers Illinois' contribution to theCorn Belt. This area of fertile soil typifies the landscape that helped make Illinois one of the top five corn producing states, one of the leading agricultural states in the nation and gave Illinois one of its nicknames; The Prairie State. Some call the Till Plains section of Illinois the Garden Spot of the Nation.The Shawnee Hills:TheShawnee Hillsregion stretches across the southern part of Illinois south of the Central Plains. This small strip of land, ranging from five to 40 miles wide and about 70 miles long is characterized by higher elevations (300 to 1,065 feet). The landscape of theShawnee Hillsconsists of rivers, valleys and woodland.The Gulf Coastal:The extreme southern tip of Illinois is covered by the northern reach of the Gulf Coastal Plain that stretches north from the Gulf of Mexico. This is the land between the Ohio River on the east and the Mississippi River on the west and sometimes referred to as "Egypt" because of its resemblance to the Nile Delta. Just south of the Shawnee Hills, the Gulf Coastal Plain tends to be hilly but flattens significantly toward the Illinois border with Kentucky.Area57,918 square miles

Land Area55,593 square miles

Water Area2,325 square miles

Highest pointCharles Mound (1,235 feet above sea level)

Lowest pointMississippi River (279 feet above sea level)

Highest temperature117 degree Fahrenheit

Lowest temperature-36 degree Fahrenheit

Geographic CenterChestnut

CLIMATEIllinois has a widely-varying climate. A significant region of the state has a humid continental climate, with hot, humid summers and cold winters. The southernmost part of the state borders on humid subtropical climate with moderate winters.

Average annual rainfall varies from 1,219 mm in southern tip to around 889 mm in the northern region. Average annual snow varies from 965 mm to 356 mm. The state is vulnerable to tornadoes, with an average of 35 tornadoes occurring annually.

POPULATIONIllinois is one of the slowest growing states in the US. Between 2000 and 2010,the population of Illinois grew by a mere 3.3%, compared to a national average US population growth of 9.7%.

Illinois Population 2013

Illinois is only the 24th largest state, but it has the 5th largest population in the US with the 3rd largest city.The population of Illinois in 2013 is 12,897,625, making Illinois the fifth largest state in theUSA. This is based on a growth rate of 0.17%, which ranks 44th. You can explore more about the latest Illinois population data using the interactive tool below, or scroll down for more information.

Illinois Population GrowthIn Illinois' cities, population growth has stalled.Chicagowas, for much of its early history, one of America's fastest growing cities. Between 1850 and 1930, the city grew by at least 25% each decade, and in some decades it doubled or even tripled in size. However, from the 1960s onwards, Chicago has been steadily shrinking and a city which was home to 3.5 million people in 1960 is home to just 2.7 million today.

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