The map above shows Colorado and Idaho side by side at exactly the same scale, using equal-area projections, so their true relative sizes are preserved.
Colorado vs Idaho Geography
Land area: Colorado has a land area of 103,637 square miles (268,419 km²), while Idaho has 82,645 square miles (214,051 km²). Colorado's land area is 1.3 times (25%) larger than Idaho's.
Total area: Colorado: 104,095 square miles (269,605 km²) vs Idaho: 83,569 square miles (216,441 km²), including inland and coastal water. Colorado's total area is 1.2 times (25%) larger than Idaho's.
Length: Colorado is 467 miles (751 km) long from north to south; Idaho is 483 miles (778 km). Colorado and Idaho have about the same north-south length.
Width: Colorado spans 387 miles (622 km) east to west; Idaho spans 352 miles (566 km). Colorado's east-west width is 1.1 times (10%) wider than Idaho's.
Highest point: Colorado's highest point is Mount Elbert at 14,422 feet (4,396 m); Idaho's is Borah Peak at 12,631 feet (3,850 m). Mount Elbert is 1,791 feet higher than Borah Peak.
Lowest point: Colorado's lowest point is Arikaree River at 3,326 feet; Idaho's is Snake River at 718 feet. Idaho's lowest point is 2,608 feet lower.
Colorado vs Idaho Population and History
Population: Colorado has a population of 5,957,493 (2024), while Idaho has 2,001,619 (2024). Colorado's population is 3.0 times (198%) larger than Idaho's.
Population density: Colorado: 57.5 people per square mile vs Idaho: 24.2. Colorado's population density is 2.4 times (138%) higher than Idaho's.
Biggest city: Colorado's biggest city is Denver with 729,019 people; Idaho's is Boise with 237,963. Denver's population is 3.1 times (206%) larger than Boise's.
Largest metro area: Colorado's largest metropolitan area is Denver-Aurora-Centennial, CO metro area (3,052,498 people) vs Idaho's Boise City, ID metro area (845,877). Denver-Aurora-Centennial, CO metro area's population is 3.6 times (261%) larger than Boise City, ID metro area's.
History: Colorado: Admitted to the Union on August 1, 1876, as the 38th state. Idaho: Admitted to the Union on July 3, 1890, as the 43rd state. In its current form, Colorado is the older of the two by 14 years.
Colorado vs Idaho Economy
GDP: Colorado's GDP is $557.6 billion (2024) vs Idaho's $129.0 billion. Colorado's economic output is 4.3 times (332%) larger than Idaho's.
GDP per capita: Colorado: $93,602 per person vs Idaho: $64,457. Colorado's GDP per capita is 1.5 times (45%) higher than Idaho's.
Average income: Colorado: $83,055 vs Idaho: $62,323 average income per person (per capita personal income). Colorado's average income is 1.3 times (33%) higher than Idaho's.
Colorado vs Idaho Counties
Number of counties: Colorado has 64 counties, while Idaho has 44. Colorado's county count is 1.5 times (45%) higher than Idaho's.
Biggest county by area: Colorado's largest county is Las Animas County at 4,773 square miles; Idaho's is Idaho County at 8,478 square miles. Idaho County's land area is 1.8 times (78%) larger than Las Animas County's.
Smallest county by area: Colorado: Broomfield County (33 sq mi) vs Idaho: Payette County (407 sq mi). Payette County's land area is 12.3 times larger than Broomfield County's.
Most populous county: Colorado: El Paso County (752,772 people) vs Idaho: Ada County (535,799 people). El Paso County's population is 1.4 times (40%) larger than Ada County's.
Least populous county: Colorado: Hinsdale County (747 people) vs Idaho: Clark County (794 people). Clark County's population is 1.1 times (6%) larger than Hinsdale County's.
Richest county: Colorado: Pitkin County ($275,044 per capita income) vs Idaho: Blaine County ($202,612). Pitkin County's income is 1.4 times (36%) richer than Blaine County's.
Poorest county: Colorado: Crowley County ($27,232 per capita income) vs Idaho: Madison County ($29,485). Madison County's income is 1.1 times (8%) richer than Crowley County's.
Colorado vs Idaho Taxes
State income tax: Colorado has a top income tax rate of 4.4%, while Idaho has a top income tax rate of 5.3%. Idaho's top rate is 0.9 percentage points higher.
Property tax: Colorado: 0.49% effective rate vs Idaho: 0.43% of home value per year. Colorado's rate is 0.06 percentage points higher.
Sales tax: Colorado: 7.89% combined state and average local rate vs Idaho: 6.03%. Colorado's combined rate is 1.86 percentage points higher.
Official Websites
Colorado official website · Idaho official website
More Size Comparisons
All Colorado 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.