The map above shows Illinois and Mississippi side by side at exactly the same scale, using equal-area projections, so their true relative sizes are preserved.
Illinois vs Mississippi Geography
Land area: Illinois has a land area of 55,513 square miles (143,778 km²), while Mississippi has 46,925 square miles (121,534 km²). Illinois' land area is 1.2 times (18%) larger than Mississippi's.
Total area: Illinois: 57,913 square miles (149,995 km²) vs Mississippi: 48,436 square miles (125,448 km²), including inland and coastal water. Illinois' total area is 1.2 times (20%) larger than Mississippi's.
Length: Illinois is 390 miles (628 km) long from north to south; Mississippi is 337 miles (542 km). Illinois' north-south length is 1.2 times (16%) longer than Mississippi's.
Width: Illinois spans 283 miles (456 km) east to west; Mississippi spans 340 miles (547 km). Mississippi's east-west width is 1.2 times (20%) wider than Illinois'.
Highest point: Illinois's highest point is Charles Mound at 1,232 feet (376 m); Mississippi's is Woodall Mountain at 805 feet (245 m). Charles Mound is 427 feet higher than Woodall Mountain.
Lowest point: Illinois's lowest point is Mississippi River at 292 feet; Mississippi's is Gulf of Mexico at 0 feet. Mississippi's lowest point is 292 feet lower.
Illinois vs Mississippi Population and History
Population: Illinois has a population of 12,710,158 (2024), while Mississippi has 2,943,045 (2024). Illinois' population is 4.3 times (332%) larger than Mississippi's.
Population density: Illinois: 229.0 people per square mile vs Mississippi: 62.7. Illinois' population density is 3.7 times (265%) higher than Mississippi's.
Biggest city: Illinois's biggest city is Chicago with 2,721,308 people; Mississippi's is Jackson with 141,449. Chicago's population is 19.2 times larger than Jackson's.
Largest metro area: Illinois's largest metropolitan area is Chicago-Naperville-Elgin, IL-IN metro area (9,408,576 people) vs Mississippi's Memphis, TN-MS-AR metro area (1,339,345). Chicago-Naperville-Elgin, IL-IN metro area's population is 7.0 times (602%) larger than Memphis, TN-MS-AR metro area's.
History: Illinois: Admitted to the Union on December 3, 1818, as the 21st state. Mississippi: Admitted to the Union on December 10, 1817, as the 20th state. In its current form, Mississippi is the older of the two by 1 years.
Illinois vs Mississippi Economy
GDP: Illinois's GDP is $1,148.1 billion (2024) vs Mississippi's $158.2 billion. Illinois' economic output is 7.3 times (626%) larger than Mississippi's.
GDP per capita: Illinois: $90,330 per person vs Mississippi: $53,751. Illinois' GDP per capita is 1.7 times (68%) higher than Mississippi's.
Average income: Illinois: $74,522 vs Mississippi: $52,074 average income per person (per capita personal income). Illinois' average income is 1.4 times (43%) higher than Mississippi's.
Illinois vs Mississippi Counties
Number of counties: Illinois has 102 counties, while Mississippi has 82. Illinois' county count is 1.2 times (24%) higher than Mississippi's.
Biggest county by area: Illinois's largest county is McLean County at 1,183 square miles; Mississippi's is Yazoo County at 922 square miles. McLean County's land area is 1.3 times (28%) larger than Yazoo County's.
Smallest county by area: Illinois: Putnam County (160 sq mi) vs Mississippi: Alcorn County (400 sq mi). Alcorn County's land area is 2.5 times (150%) larger than Putnam County's.
Most populous county: Illinois: Cook County (5,182,617 people) vs Mississippi: Harrison County (213,730 people). Cook County's population is 24.2 times larger than Harrison County's.
Least populous county: Illinois: Hardin County (3,550 people) vs Mississippi: Issaquena County (1,295 people). Hardin County's population is 2.7 times (174%) larger than Issaquena County's.
Richest county: Illinois: Cumberland County ($104,890 per capita income) vs Mississippi: Madison County ($90,668). Cumberland County's income is 1.2 times (16%) richer than Madison County's.
Poorest county: Illinois: Lawrence County ($43,606 per capita income) vs Mississippi: Issaquena County ($27,264). Lawrence County's income is 1.6 times (60%) richer than Issaquena County's.
Illinois vs Mississippi Taxes
State income tax: Illinois has a top income tax rate of 4.95%, while Mississippi has a top income tax rate of 4%. Illinois's top rate is 0.95 percentage points higher.
Property tax: Illinois: 1.92% effective rate vs Mississippi: 0.65% of home value per year. Illinois's rate is 1.27 percentage points higher.
Sales tax: Illinois: 8.98% combined state and average local rate vs Mississippi: 7.06%. Illinois's combined rate is 1.92 percentage points higher.
Official Websites
Illinois official website · Mississippi official website
More Size Comparisons
All Illinois size comparisons · All Mississippi 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.