The capital of Illinois is Springfield.
The Postal Code for Illinois: IL
The typical abbreviation for Illinois: Ill.
Time Zone:
The state of Illinois is in the Central Time (CST/CDT) zone and observes daylight saving time.
| Note: |
Starting in 2007, Daylight Savings Time will be begin 3 weeks earlier and end 1 week later.
Click here for details. |
When the people of Illinois refer to themselves: Illinoisan
Population: According to the 2006 Census estimates, Illinois has a population of 12,831,970 people.
This represents 4.29% of the national total, making it the 5th most populous state.
The following are population changes since the last Census. The population counts after year 2000 are estimates.
| Year | Population | Change |
| 2006 | 12,831,970 | +0.52% since 2005 |
| 2005 | 12,765,427 | +0.41% since 2004 |
| 2004 | 12,713,548 | +0.51% since 2003 |
| 2003 | 12,649,087 | +0.43% since 2002 |
| 2002 | 12,595,003 | +0.56% since 2001 |
| 2001 | 12,524,663 | +0.85% since 2000 |
| 2000 | 12,419,293 | Last Census Count |
Area:
The area of Illinois is 57,914 square miles (149,996.57 km²).
This represents 1.53% of the national total.
Illinois ranks as the 25th largest state.
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Density:
The population density of Illinois is 230.86 people per square mile (89.13 people/km²).
Illinois ranks 12th in population density.
Nicknames for Illinois: "The Prairie State"; "Land of Lincoln"
State Motto: "State Sovereignty, National Union"
State Bird: Cardinal (cardinalis cardinalis)
State Tree: White Oak (quercus alba)
State Flower: Purple Violet (viola)
State Song: "Illinois"
Statehood:
Illinois became the 21st state on Dec 3, 1818.
Useful State Links
The state website for Illinois can be found at:
The portal for Illinois tourism:
For information about Illinois fishing regulations and licenses requirements:
For information about Illinois hunting regulations and licenses requirements:
Communities Ranked by Population (Top-15)
 
| Rank | City | 2005
Population | National
Rank |
| 1 | Chicago | 2,842,518 | 3 |
| 2 | Rockford | 152,916 | 138 |
| 3 | Aurora | 168,181 | 148 |
| 4 | Naperville | 141,579 | 171 |
| 5 | Peoria | 112,685 | |
| 6 | Springfield | 115,668 | |
| 7 | Joliet | 136,208 | |
| 8 | Elgin | 98,645 | |
| 9 | Waukegan | 91,396 | |
| 10 | Cicero | 82,741 | |
| 11 | Decatur | 77,836 | |
| 12 | Arlington Heights | 74,620 | |
| 13 | Schaumburg | 72,805 | |
| 14 | Evanston | 75,236 | |
| 15 | Champaign | 71,568 | |
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Miscellaneous Information
| Census Region: 2 (Midwest) |
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| Census Division: 3 (East North-Central) |
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| State FIPS-55 Code: 17 |
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| Office of Management and Budget (OMB): Region V / Region 5 |
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| ISO-3166-2 Code: US-IL |
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