The map above shows Illinois and Kentucky side by side at exactly the same scale, using equal-area projections, so their true relative sizes are preserved.
Illinois vs Kentucky Geography
Land area
- Illinois has a land area of 55,513 square miles (143,778 km²), while Kentucky has 39,485 square miles (102,267 km²).
- Illinois' land area is 1.4 times (41%) larger than Kentucky's.
Total area
- Illinois: 57,913 square miles (149,995 km²) vs Kentucky: 40,406 square miles (104,651 km²), including inland and coastal water.
- Illinois' total area is 1.4 times (43%) larger than Kentucky's.
Length
- Illinois is 390 miles (628 km) long from north to south; Kentucky is 257 miles (414 km).
- Illinois' north-south length is 1.5 times (52%) longer than Kentucky's.
Width
- Illinois spans 283 miles (456 km) east to west; Kentucky spans 418 miles (672 km).
- Kentucky's east-west width is 1.5 times (48%) wider than Illinois'.
Highest point
- Illinois's highest point is Charles Mound at 1,232 feet (376 m); Kentucky's is Black Mountain at 4,134 feet (1,260 m).
- Black Mountain is 2,902 feet higher than Charles Mound.
Lowest point
- Illinois's lowest point is Mississippi River at 292 feet; Kentucky's is Mississippi River at 270 feet.
- Kentucky's lowest point is 22 feet lower.
Illinois vs Kentucky Population and History
Population
- Illinois has a population of 12,710,158 (2024), while Kentucky has 4,588,372 (2024).
- Illinois' population is 2.8 times (177%) larger than Kentucky's.
Population density
- Illinois: 229.0 people per square mile vs Kentucky: 116.2.
- Illinois' population density is 2.0 times (97%) higher than Kentucky's.
Biggest city
- Illinois's biggest city is Chicago with 2,721,308 people; Kentucky's is Louisville with 640,796.
- Chicago's population is 4.2 times (325%) larger than Louisville's.
Largest metro area
- Illinois's largest metropolitan area is Chicago-Naperville-Elgin, IL-IN metro area (9,408,576 people) vs Kentucky's Cincinnati, OH-KY-IN metro area (2,302,815).
- Chicago-Naperville-Elgin, IL-IN metro area's population is 4.1 times (309%) larger than Cincinnati, OH-KY-IN metro area's.
History
- Illinois: Admitted to the Union on December 3, 1818, as the 21st state.
- Kentucky: Admitted to the Union on June 1, 1792, as the 15th state.
- In its current form, Kentucky is the older of the two by 26 years.
Illinois vs Kentucky Economy
GDP
- Illinois's GDP is $1,148.1 billion (2024) vs Kentucky's $295.4 billion.
- Illinois' economic output is 3.9 times (289%) larger than Kentucky's.
GDP per capita
- Illinois: $90,330 per person vs Kentucky: $64,375.
- Illinois' GDP per capita is 1.4 times (40%) higher than Kentucky's.
Average income
- Illinois: $74,522 vs Kentucky: $58,256 average income per person (per capita personal income).
- Illinois' average income is 1.3 times (28%) higher than Kentucky's.
Illinois vs Kentucky Counties
Number of counties
- Illinois has 102 counties, while Kentucky has 120.
- Kentucky's county count is 1.2 times (18%) higher than Illinois'.
Biggest county by area
- Illinois's largest county is McLean County at 1,183 square miles; Kentucky's is Pike County at 786 square miles.
- McLean County's land area is 1.5 times (50%) larger than Pike County's.
Smallest county by area
- Illinois: Putnam County (160 sq mi) vs Kentucky: Gallatin County (98 sq mi).
- Putnam County's land area is 1.6 times (63%) larger than Gallatin County's.
Most populous county
- Illinois: Cook County (5,182,617 people) vs Kentucky: Jefferson County (793,881 people).
- Cook County's population is 6.5 times (553%) larger than Jefferson County's.
Least populous county
- Illinois: Hardin County (3,550 people) vs Kentucky: Robertson County (2,382 people).
- Hardin County's population is 1.5 times (49%) larger than Robertson County's.
Richest county
- Illinois: Cumberland County ($104,890 per capita income) vs Kentucky: Oldham County ($87,137).
- Cumberland County's income is 1.2 times (20%) richer than Oldham County's.
Poorest county
- Illinois: Lawrence County ($43,606 per capita income) vs Kentucky: Elliott County ($31,817).
- Lawrence County's income is 1.4 times (37%) richer than Elliott County's.
Illinois vs Kentucky Taxes
State income tax
- Illinois has a top income tax rate of 4.95%, while Kentucky has a top income tax rate of 3.5%.
- Illinois's top rate is 1.45 percentage points higher.
Property tax
- Illinois: 1.92% effective rate vs Kentucky: 0.71% of home value per year.
- Illinois's rate is 1.21 percentage points higher.
Sales tax
- Illinois: 8.98% combined state and average local rate vs Kentucky: 6%.
- Illinois's combined rate is 2.98 percentage points higher.
Official Websites
Illinois official website · Kentucky official website
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More Size Comparisons
All Illinois size comparisons · All Kentucky size comparisons
Area, elevation and boundary figures come from official national statistics and US Census Bureau and Natural Earth boundary data; US state population, economic, county and tax figures come from the US Census Bureau, the Bureau of Economic Analysis and the Tax Foundation. Figures are rounded and for general reference.