Illinois Counties Map: Click All 102 Counties

How many counties are in Illinois?

Illinois has 102 counties. Five states have more, and 44 have fewer.

Illinois has 102 counties. Cook County, home to Chicago, has more people than 27 entire states and holds about two of every five Illinoisans. The capital, Springfield, is in Sangamon County in the middle of the state.

How Illinois's counties were formed

Illinois's oldest counties are St. Clair, created in 1790 by the governor of the Northwest Territory, and Randolph, created in 1795. Settlement moved north from the river towns of the south, so northern Illinois was the last to be divided. Ford County, created in 1859, was the 102nd and last. Cook County was formed in 1831, two years before Chicago was incorporated as a town.

Illinois regions and the counties in each

Illinois maps often show six regions. Chicagoland is Cook and the collar counties. Northern Illinois includes Winnebago (Rockford) and the Rock River counties. Central Illinois is flat prairie farm country: Sangamon (Springfield), McLean (Bloomington), Champaign and Peoria. Western Illinois sits along the Mississippi, with Rock Island and Adams (Quincy). The Metro East counties, Madison and St. Clair, face St. Louis, and Southern Illinois, or Little Egypt, ends at Alexander County, where Cairo sits between the Ohio and Mississippi rivers.

Notable places on the Illinois county map

Charles Mound, the state's highest point at 1,235 feet, is in Jo Daviess County near the Wisconsin line. The sandstone bluffs of the Garden of the Gods are in Saline County in the Shawnee National Forest, and Starved Rock State Park lines the Illinois River in LaSalle County. Springfield, in Sangamon County, holds Abraham Lincoln's home and tomb.

Illinois counties map: the biggest and smallest

McLean County is the largest county in Illinois, with 1,183 square miles of land, about 2% of the state. That's more land than the whole state of Rhode Island. Putnam County is the smallest, at 160 square miles.

The smallest counties by land area are Putnam County (160 sq mi), Hardin County (177 sq mi) and Pulaski County (199 sq mi).

Which counties in Illinois have the most people?

Cook County has the most people, about 5,182,617 in the Census Bureau's July 2024 estimate, or 41% of everyone in Illinois. The three biggest counties together hold 54% of the state's 12,710,158 people. Hardin County has the fewest, about 3,550.

The most crowded is Cook County, with about 5,485 people per square mile. The emptiest is Pope County, with about 10 people per square mile. Comparing the two is a quick way to show children that a big county on the map isn't always a big county in people.

What county is Springfield in?

Springfield, the capital of Illinois, is in Sangamon County. Sangamon County ranks 11th of 102 by population. Illinois is called the Prairie State, and it became the 21st state in 1818.

Counties on the Illinois border

Learning the edge of the map first gives children a frame to fill in. Illinois shares a border with Indiana, Iowa, Kentucky, Missouri and Wisconsin.

How Illinois's counties compare with other states

Illinois ranks 24th among the 50 states in land area and 6th in population. Its average county covers about 544 square miles and holds about 124,609 people. Across the 50 states, the average county-level area covers about 1,139 square miles and holds about 109,381 people, so Illinois's counties are smaller than usual in size. Small counties pack more names into the same space, so zooming in helps.

Landmarks for learning the counties of Illinois

• Cook County and its collar counties (Lake, McHenry, Kane, DuPage, Will) fill the northeast corner on Lake Michigan.
• The Mississippi River forms the whole western border.
• The southern tip, between the Ohio and Mississippi rivers, is the region called Little Egypt.

With 102 counties, work one region at a time: study it with names on, then take a Practice round and stop when you've found that group. Then print the Illinois county map worksheet to check that it sticks on paper.

All 102 Illinois counties

Every county on the map, A to Z, with its land area and July 2024 population estimate.

Illinois geography for homeschoolers

Pair this map with the Midwest states and capitals quiz and the US states quiz. If you teach at home, see homeschooling in illinois, and check illinois school choice to see whether a program may help pay for Illinois history and geography curriculum. Each program decides what it covers.