The map above shows California and Idaho side by side at exactly the same scale, using equal-area projections, so their true relative sizes are preserved.
California vs Idaho Geography
Land area: California has a land area of 155,859 square miles (403,673 km²), while Idaho has 82,645 square miles (214,051 km²). California's land area is 1.9 times (89%) larger than Idaho's.
Total area: California: 163,694 square miles (423,965 km²) vs Idaho: 83,569 square miles (216,441 km²), including inland and coastal water. California's total area is 2.0 times (96%) larger than Idaho's.
Length: California is 761 miles (1,224 km) long from north to south; Idaho is 483 miles (778 km). California's north-south length is 1.6 times (58%) longer than Idaho's.
Width: California spans 706 miles (1,137 km) east to west; Idaho spans 352 miles (566 km). California's east-west width is 2.0 times (101%) wider than Idaho's.
Highest point: California's highest point is Mount Whitney at 14,484 feet (4,415 m); Idaho's is Borah Peak at 12,631 feet (3,850 m). Mount Whitney is 1,853 feet higher than Borah Peak.
Lowest point: California's lowest point is Death Valley at -279 feet; Idaho's is Snake River at 718 feet. California's lowest point is 997 feet lower.
California vs Idaho Population and History
Population: California has a population of 39,431,263 (2024), while Idaho has 2,001,619 (2024). California's population is 19.7 times larger than Idaho's.
Population density: California: 253.0 people per square mile vs Idaho: 24.2. California's population density is 10.5 times higher than Idaho's.
Biggest city: California's biggest city is Los Angeles with 3,878,704 people; Idaho's is Boise with 237,963. Los Angeles' population is 16.3 times larger than Boise's.
Largest metro area: California's largest metropolitan area is Los Angeles-Long Beach-Anaheim, CA metro area (12,927,614 people) vs Idaho's Boise City, ID metro area (845,877). Los Angeles-Long Beach-Anaheim, CA metro area's population is 15.3 times larger than Boise City, ID metro area's.
History: California: Admitted to the Union on September 9, 1850, as the 31st state. Idaho: Admitted to the Union on July 3, 1890, as the 43rd state. In its current form, California is the older of the two by 40 years.
California vs Idaho Economy
GDP: California's GDP is $4,048.1 billion (2024) vs Idaho's $129.0 billion. California's economic output is 31.4 times larger than Idaho's.
GDP per capita: California: $102,662 per person vs Idaho: $64,457. California's GDP per capita is 1.6 times (59%) higher than Idaho's.
Average income: California: $86,232 vs Idaho: $62,323 average income per person (per capita personal income). California's average income is 1.4 times (38%) higher than Idaho's.
California vs Idaho Counties
Number of counties: California has 58 counties, while Idaho has 44. California's county count is 1.3 times (32%) higher than Idaho's.
Biggest county by area: California's largest county is San Bernardino County at 20,068 square miles; Idaho's is Idaho County at 8,478 square miles. San Bernardino County's land area is 2.4 times (137%) larger than Idaho County's.
Smallest county by area: California: San Francisco County (47 sq mi) vs Idaho: Payette County (407 sq mi). Payette County's land area is 8.7 times (771%) larger than San Francisco County's.
Most populous county: California: Los Angeles County (9,757,179 people) vs Idaho: Ada County (535,799 people). Los Angeles County's population is 18.2 times larger than Ada County's.
Least populous county: California: Alpine County (1,099 people) vs Idaho: Clark County (794 people). Alpine County's population is 1.4 times (38%) larger than Clark County's.
Richest county: California: Marin County ($190,891 per capita income) vs Idaho: Blaine County ($202,612). Blaine County's income is 1.1 times (6%) richer than Marin County's.
Poorest county: California: Trinity County ($42,191 per capita income) vs Idaho: Madison County ($29,485). Trinity County's income is 1.4 times (43%) richer than Madison County's.
California vs Idaho Taxes
State income tax: California has a top income tax rate of 13.3%, while Idaho has a top income tax rate of 5.3%. California's top rate is 8 percentage points higher.
Property tax: California: 0.71% effective rate vs Idaho: 0.43% of home value per year. California's rate is 0.28 percentage points higher.
Sales tax: California: 9.03% combined state and average local rate vs Idaho: 6.03%. California's combined rate is 3 percentage points higher.
Official Websites
California official website · Idaho official website
More Size Comparisons
All California size comparisons · All Idaho 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.