The map above shows Illinois and Washington side by side at exactly the same scale, using equal-area projections, so their true relative sizes are preserved.
Illinois vs Washington Geography
Land area
- Illinois has a land area of 55,513 square miles (143,778 km²), while Washington has 66,455 square miles (172,119 km²).
- Washington's land area is 1.2 times (20%) larger than Illinois'.
Total area
- Illinois: 57,913 square miles (149,995 km²) vs Washington: 71,301 square miles (184,668 km²), including inland and coastal water.
- Washington's total area is 1.2 times (23%) larger than Illinois'.
Length
- Illinois is 390 miles (628 km) long from north to south; Washington is 238 miles (383 km).
- Illinois' north-south length is 1.6 times (64%) longer than Washington's.
Width
- Illinois spans 283 miles (456 km) east to west; Washington spans 399 miles (641 km).
- Washington's east-west width is 1.4 times (41%) wider than Illinois'.
Highest point
- Illinois's highest point is Charles Mound at 1,232 feet (376 m); Washington's is Mount Rainier at 14,409 feet (4,392 m).
- Mount Rainier is 13,177 feet higher than Charles Mound.
Lowest point
- Illinois's lowest point is Mississippi River at 292 feet; Washington's is Pacific Ocean at 0 feet.
- Washington's lowest point is 292 feet lower.
Illinois vs Washington Population and History
Population
- Illinois has a population of 12,710,158 (2024), while Washington has 7,958,180 (2024).
- Illinois' population is 1.6 times (60%) larger than Washington's.
Population density
- Illinois: 229.0 people per square mile vs Washington: 119.8.
- Illinois' population density is 1.9 times (91%) higher than Washington's.
Biggest city
- Illinois's biggest city is Chicago with 2,721,308 people; Washington's is Seattle with 780,995.
- Chicago's population is 3.5 times (248%) larger than Seattle's.
Largest metro area
- Illinois's largest metropolitan area is Chicago-Naperville-Elgin, IL-IN metro area (9,408,576 people) vs Washington's Seattle-Tacoma-Bellevue, WA metro area (4,145,494).
- Chicago-Naperville-Elgin, IL-IN metro area's population is 2.3 times (127%) larger than Seattle-Tacoma-Bellevue, WA metro area's.
History
- Illinois: Admitted to the Union on December 3, 1818, as the 21st state.
- Washington: Admitted to the Union on November 11, 1889, as the 42nd state.
- In its current form, Illinois is the older of the two by 71 years.
Illinois vs Washington Economy
GDP
- Illinois's GDP is $1,148.1 billion (2024) vs Washington's $856.0 billion.
- Illinois' economic output is 1.3 times (34%) larger than Washington's.
GDP per capita
- Illinois: $90,330 per person vs Washington: $107,564.
- Washington's GDP per capita is 1.2 times (19%) higher than Illinois'.
Average income
- Illinois: $74,522 vs Washington: $85,187 average income per person (per capita personal income).
- Washington's average income is 1.1 times (14%) higher than Illinois'.
Illinois vs Washington Counties
Number of counties
- Illinois has 102 counties, while Washington has 39.
- Illinois' county count is 2.6 times (162%) higher than Washington's.
Biggest county by area
- Illinois's largest county is McLean County at 1,183 square miles; Washington's is Okanogan County at 5,266 square miles.
- Okanogan County's land area is 4.5 times (345%) larger than McLean County's.
Smallest county by area
- Illinois: Putnam County (160 sq mi) vs Washington: San Juan County (174 sq mi).
- San Juan County's land area is 1.1 times (9%) larger than Putnam County's.
Most populous county
- Illinois: Cook County (5,182,617 people) vs Washington: King County (2,340,211 people).
- Cook County's population is 2.2 times (121%) larger than King County's.
Least populous county
- Illinois: Hardin County (3,550 people) vs Washington: Garfield County (2,404 people).
- Hardin County's population is 1.5 times (48%) larger than Garfield County's.
Richest county
- Illinois: Cumberland County ($104,890 per capita income) vs Washington: King County ($128,684).
- King County's income is 1.2 times (23%) richer than Cumberland County's.
Poorest county
- Illinois: Lawrence County ($43,606 per capita income) vs Washington: Ferry County ($50,456).
- Ferry County's income is 1.2 times (16%) richer than Lawrence County's.
Illinois vs Washington Taxes
State income tax
- Illinois has a top income tax rate of 4.95%, while Washington has a 9% tax on capital gains only.
Property tax
- Illinois: 1.92% effective rate vs Washington: 0.79% of home value per year.
- Illinois's rate is 1.13 percentage points higher.
Sales tax
- Illinois: 8.98% combined state and average local rate vs Washington: 9.57%.
- Washington's combined rate is 0.59 percentage points higher.
Official Websites
Illinois official website · Washington official website
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More Size Comparisons
All Illinois size comparisons · All Washington 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.