Community Profiles Now Include More Places to Explore

We've enhanced the "Places" section of our Community Profiles to make it easier for you to discover popular nearby places.

Illinois Gazetteer

Illinois - Basic Information

Became a State: December 3, 1818 - 21st State
Population: 12,830,632 (2010 Census) - Ranks 5th
Land Area: 55,518.9 square miles - Ranks 24th
Population Density: 231.1 persons per square mile - Ranks 12nd
Housing Units: 5,296,715 (2010 Census)
Housing Unit Density: 95.4 housing units per square mile
July 1, 2023 Estimates: Illinois Data and Demographics
State Capital: Springfield
State Website: Official State of Illinois Website
Illinois State Flag
Illinois state flag

Quick & Easy Ways to...

  1. Get Current Demographic Data for Cities, Towns, and ZIP Codes
  2. View Boundary Maps, for Cities, Towns, and ZIP Codes
  3. Locate Physical, Cultural, and Historical Features

Use HTL Address Research for a Illinois Address and get...

Boundary Maps, Demographic Data, School Zones Review maps and data for the neighborhood, city, county, ZIP Code, and school zone. July 1, 2023, data includes home values, household income, percentage of homes owned, rented or vacant, etc.

Illinois Neighborhood Explorer

NOTE: The BEST tool for researching a neighborhood is the HTL Address Research Tool (above). However, if you do not have an address, the Illinois Neighborhood Explorer is the SECOND-BEST-TOOL to research a neighborhood (it provides a subset of the information that the Address Research Tool provides), but you can get a report by simply marking a spot on a map.

The Illinois Neighborhood Explorer helps you to research any Illinois neighborhood (census block group) and get home values, average household income, owner/renter/ occupancy rates, projected growth rates, boundary maps, comparisons to other communities, and much more.

Simply mark a spot on a state map and you'll have your results within 3-seconds!

Illinois Neighborhood Explorer

Illinois History

Illinois State Flower
Illinois State Flower - Illinois Native Violet

The area of Illinois was part of the original territory of the United States, being part of lands ceded by four states to the United States and designated in 1787 as the "Territory northwest of the River Ohio." Illinois Territory was organized on February 3, 1809, from the western part of Indiana Territory, and included all of present-day Illinois, most of Wisconsin, the western part of the Upper Peninsula of Michigan, and northeastern Minnesota.

Although the territory had not yet been legally established, census data for Illinois are available beginning with the 1800 census. The 1810 population is for the entire area of the Illinois Territory, including territory not in the present state. For an explanation of the revision to the 1800 population of Illinois, see Richard L. Forstall, Population of States and Counties of the United States: 1790-1990, Washington, DC: U.S. Government Printing Office, 1996, page 48.

Data for the legally established state of Illinois are available beginning with the 1820 census.

Illinois Geographical Areas

See: Geographic Terms & Concepts

Counties & County Equivalents

Interactive Map of Illinois Counties | Static Overview Map of Illinois Counties

There are 102 counties in Illinois. All counties are functioning governmental units; each is governed by a board with between 5 and 29 members.

County Subdivisions

There are 1,710 county subdivisions in Illinois known as minor civil divisions (MCDs); 85 counties have functioning, but not necessarily active, townships and 17 counties have nonfunctioning election precincts. There are 1,432 townships and 274 election precincts. Chicago city is independent of any MCD and serves as an MCD equivalent in two counties, creating two county subdivisions. There are also two undefined MCDs that cover the Illinois portion of Lake Michigan. Alexander, Calhoun, Edwards, Hardin, Johnson, Massac, Menard, Monroe, Morgan, Perry, Pope, Pulaski, Randolph, Scott, Union, Wabash, and Williamson counties have election precincts. All other counties have townships. The governing body for each township is an elected township supervisor and a board of trustees.

Places (Incorporated Cities, Towns & Census Designated Places (CDPs))

Illinois State Bird
Illinois State Bird - Cardinal

Illinois has 1,367 places, 1,299 incorporated places and 68 census designated places (CDPs). The incorporated places consist of 300 cities, 16 towns, and 983 villages. The minimum population to incorporate as a city is 2,500.  For a village the minimum population for incorporation ranges from 200 (in counties with a population less than 150,000) to 2,500.  Incorporated places are dependent within county subdivision with the following exceptions:

  • Independent of any township
    • Chicago city
  • Coextensive with a single township
    • Alton
    • Belleville
    • Berwyn
    • Bloomington
    • Champaign
    • Cicero
    • East St. Louis
    • Evanston
    • Freeport
    • Galesburg
    • Godfrey
    • Macomb
    • Oak Park
    • Quincy
    • River Forest
    • Urbana
    • Warsaw
    • Zion
  • Coextensive with a single precinct
    • Cairo
    • Golconda
    • Valmeyer
  • Coextensive with multiple whole precincts
    • Jacksonville
    • South Jacksonville
    • Waterloo
  • Coextensive with one more precincts in Monroe County, but also has part of one township in St. Clair County
    • Columbia city
    • Hecker village
  • Contain one or more whole precincts and parts of others
    • Du Quion
    • Metropolis
    • Petersburg
    • Pinckneyville

Alphabetical List of Cities, Towns, CDPs and Other Populated Places
A | B | C | D | E | F | G | H | I | J | K | L | M | N | O | P | Q, R | S | T | U, V | W, X, Y, Z

Illinois Civil Features

Illinois Civil Features: Political Subdivisions, Native Areas, Land Grants, etc. - sorted by Census Class Codes.

Metropolitan and Micropolitan Statistical Areas

There are 12 Metropolitan and 17 Micropolitan Statistical Areas in Illinois. IL Metopolitan & Micropolitan Areas

Illinois ZIP Code Tabulation Areas

There are 1,384 ZIP Code tabulation areas (ZCTAs) in Illinois. View Illinois ZIP Codes and ZIP Code Maps.

School Districts

There are 379 elementary school districts, 104 secondary school districts, and 389 unified school districts in Illinois. View Illinois Public and Private Schools.

Congressional Districts

Illinois has 19 congressional districts. An interactive map shows the contact information for each Representative as well as the boundaries for each Illinois district. View Map of Illinois Congressional Districts.

State Legislative Districts

There are 59 state senate districts and 118 state house districts in Illinois. There is also one state house district undefined and one state senate district undefined each comprising the portion of Illinois in Lake Michigan.

Illinois Physical, Cultural and Historic Features

  1. Illinois Physical Features such as lakes, islands, streams, valleys, summits, etc.
  2. Illinois Cultural Features such as schools, churches, hospitals, parks, dams, reservoirs, etc.
  3. Illinois Historical Features and Illinois Historic Landmarks

Illinois Maps

  • To find a ZIP Code: input the address in the top-left search box of any ZIP Code Map.
  • To find the County: input the address in the top-left search box of the interactive IL map.
  • To find the School Attendance Zone: input the address in the top-left search box of any IL school map

Quick & Easy Ways to...

  1. Get Current Demographic Data for Cities, Towns, and ZIP Codes
  2. View Boundary Maps, for Cities, Towns, and ZIP Codes
  3. Locate Physical, Cultural, and Historical Features

Illinois Census Data Comparison Tool

Compare Illinois July 1, 2023 Data
Highest or Lowest: