The map above shows California and Illinois side by side at exactly the same scale, using equal-area projections, so their true relative sizes are preserved.
California vs Illinois Geography
Land area: California has a land area of 155,859 square miles (403,673 km²), while Illinois has 55,513 square miles (143,778 km²). California's land area is 2.8 times (181%) larger than Illinois'.
Total area: California: 163,694 square miles (423,965 km²) vs Illinois: 57,913 square miles (149,995 km²), including inland and coastal water. California's total area is 2.8 times (183%) larger than Illinois'.
Length: California is 761 miles (1,224 km) long from north to south; Illinois is 390 miles (628 km). California's north-south length is 2.0 times (95%) longer than Illinois'.
Width: California spans 706 miles (1,137 km) east to west; Illinois spans 283 miles (456 km). California's east-west width is 2.5 times (149%) wider than Illinois'.
Highest point: California's highest point is Mount Whitney at 14,484 feet (4,415 m); Illinois's is Charles Mound at 1,232 feet (376 m). Mount Whitney is 13,252 feet higher than Charles Mound.
Lowest point: California's lowest point is Death Valley at -279 feet; Illinois's is Mississippi River at 292 feet. California's lowest point is 571 feet lower.
California vs Illinois Population and History
Population: California has a population of 39,431,263 (2024), while Illinois has 12,710,158 (2024). California's population is 3.1 times (210%) larger than Illinois'.
Population density: California: 253.0 people per square mile vs Illinois: 229.0. California's population density is 1.1 times (10%) higher than Illinois'.
Biggest city: California's biggest city is Los Angeles with 3,878,704 people; Illinois's is Chicago with 2,721,308. Los Angeles' population is 1.4 times (43%) larger than Chicago's.
Largest metro area: California's largest metropolitan area is Los Angeles-Long Beach-Anaheim, CA metro area (12,927,614 people) vs Illinois's Chicago-Naperville-Elgin, IL-IN metro area (9,408,576). Los Angeles-Long Beach-Anaheim, CA metro area's population is 1.4 times (37%) larger than Chicago-Naperville-Elgin, IL-IN metro area's.
History: California: Admitted to the Union on September 9, 1850, as the 31st state. Illinois: Admitted to the Union on December 3, 1818, as the 21st state. In its current form, Illinois is the older of the two by 32 years.
California vs Illinois Economy
GDP: California's GDP is $4,048.1 billion (2024) vs Illinois's $1,148.1 billion. California's economic output is 3.5 times (253%) larger than Illinois'.
GDP per capita: California: $102,662 per person vs Illinois: $90,330. California's GDP per capita is 1.1 times (14%) higher than Illinois'.
Average income: California: $86,232 vs Illinois: $74,522 average income per person (per capita personal income). California's average income is 1.2 times (16%) higher than Illinois'.
California vs Illinois Counties
Number of counties: California has 58 counties, while Illinois has 102. Illinois' county count is 1.8 times (76%) higher than California's.
Biggest county by area: California's largest county is San Bernardino County at 20,068 square miles; Illinois's is McLean County at 1,183 square miles. San Bernardino County's land area is 17.0 times larger than McLean County's.
Smallest county by area: California: San Francisco County (47 sq mi) vs Illinois: Putnam County (160 sq mi). Putnam County's land area is 3.4 times (243%) larger than San Francisco County's.
Most populous county: California: Los Angeles County (9,757,179 people) vs Illinois: Cook County (5,182,617 people). Los Angeles County's population is 1.9 times (88%) larger than Cook County's.
Least populous county: California: Alpine County (1,099 people) vs Illinois: Hardin County (3,550 people). Hardin County's population is 3.2 times (223%) larger than Alpine County's.
Richest county: California: Marin County ($190,891 per capita income) vs Illinois: Cumberland County ($104,890). Marin County's income is 1.8 times (82%) richer than Cumberland County's.
Poorest county: California: Trinity County ($42,191 per capita income) vs Illinois: Lawrence County ($43,606). Trinity County and Lawrence County have about the same income.
California vs Illinois Taxes
State income tax: California has a top income tax rate of 13.3%, while Illinois has a top income tax rate of 4.95%. California's top rate is 8.35 percentage points higher.
Property tax: California: 0.71% effective rate vs Illinois: 1.92% of home value per year. Illinois's rate is 1.21 percentage points higher.
Sales tax: California: 9.03% combined state and average local rate vs Illinois: 8.98%. California's combined rate is 0.05 percentage points higher.
Official Websites
California official website · Illinois official website
More Size Comparisons
All California size comparisons · All Illinois 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.