The map above shows Idaho and Missouri side by side at exactly the same scale, using equal-area projections, so their true relative sizes are preserved.
Idaho vs Missouri Geography
Land area: Idaho has a land area of 82,645 square miles (214,051 km²), while Missouri has 68,746 square miles (178,052 km²). Idaho's land area is 1.2 times (20%) larger than Missouri's.
Total area: Idaho: 83,569 square miles (216,441 km²) vs Missouri: 69,707 square miles (180,540 km²), including inland and coastal water. Idaho's total area is 1.2 times (20%) larger than Missouri's.
Length: Idaho is 483 miles (778 km) long from north to south; Missouri is 328 miles (529 km). Idaho's north-south length is 1.5 times (47%) longer than Missouri's.
Width: Idaho spans 352 miles (566 km) east to west; Missouri spans 437 miles (703 km). Missouri's east-west width is 1.2 times (24%) wider than Idaho's.
Highest point: Idaho's highest point is Borah Peak at 12,631 feet (3,850 m); Missouri's is Taum Sauk Mountain at 1,771 feet (540 m). Borah Peak is 10,860 feet higher than Taum Sauk Mountain.
Lowest point: Idaho's lowest point is Snake River at 718 feet; Missouri's is St. Francis River at 230 feet. Missouri's lowest point is 488 feet lower.
Idaho vs Missouri Population and History
Population: Idaho has a population of 2,001,619 (2024), while Missouri has 6,245,466 (2024). Missouri's population is 3.1 times (212%) larger than Idaho's.
Population density: Idaho: 24.2 people per square mile vs Missouri: 90.8. Missouri's population density is 3.8 times (275%) higher than Idaho's.
Biggest city: Idaho's biggest city is Boise with 237,963 people; Missouri's is Kansas City with 516,032. Kansas City's population is 2.2 times (117%) larger than Boise's.
Largest metro area: Idaho's largest metropolitan area is Boise City, ID metro area (845,877 people) vs Missouri's St. Louis, MO-IL metro area (2,811,927). St. Louis, MO-IL metro area's population is 3.3 times (232%) larger than Boise City, ID metro area's.
History: Idaho: Admitted to the Union on July 3, 1890, as the 43rd state. Missouri: Admitted to the Union on August 10, 1821, as the 24th state. In its current form, Missouri is the older of the two by 69 years.
Idaho vs Missouri Economy
GDP: Idaho's GDP is $129.0 billion (2024) vs Missouri's $448.7 billion. Missouri's economic output is 3.5 times (248%) larger than Idaho's.
GDP per capita: Idaho: $64,457 per person vs Missouri: $71,846. Missouri's GDP per capita is 1.1 times (11%) higher than Idaho's.
Average income: Idaho: $62,323 vs Missouri: $64,920 average income per person (per capita personal income). Idaho and Missouri have about the same average income.
Idaho vs Missouri Counties
Number of counties: Idaho has 44 counties, while Missouri has 115. Missouri's county count is 2.6 times (161%) higher than Idaho's.
Biggest county by area: Idaho's largest county is Idaho County at 8,478 square miles; Missouri's is Texas County at 1,177 square miles. Idaho County's land area is 7.2 times (620%) larger than Texas County's.
Smallest county by area: Idaho: Payette County (407 sq mi) vs Missouri: St. Louis city (62 sq mi). Payette County's land area is 6.6 times (559%) larger than St. Louis city's.
Most populous county: Idaho: Ada County (535,799 people) vs Missouri: St. Louis County (992,929 people). St. Louis County's population is 1.9 times (85%) larger than Ada County's.
Least populous county: Idaho: Clark County (794 people) vs Missouri: Worth County (1,872 people). Worth County's population is 2.4 times (136%) larger than Clark County's.
Richest county: Idaho: Blaine County ($202,612 per capita income) vs Missouri: St. Louis County ($104,775). Blaine County's income is 1.9 times (93%) richer than St. Louis County's.
Poorest county: Idaho: Madison County ($29,485 per capita income) vs Missouri: Douglas County ($40,515). Douglas County's income is 1.4 times (37%) richer than Madison County's.
Idaho vs Missouri Taxes
State income tax: Idaho has a top income tax rate of 5.3%, while Missouri has a top income tax rate of 4.7%. Idaho's top rate is 0.6 percentage points higher.
Property tax: Idaho: 0.43% effective rate vs Missouri: 0.79% of home value per year. Missouri's rate is 0.36 percentage points higher.
Sales tax: Idaho: 6.03% combined state and average local rate vs Missouri: 8.44%. Missouri's combined rate is 2.41 percentage points higher.
Official Websites
Idaho official website · Missouri official website
More Size Comparisons
All Idaho size comparisons · All Missouri 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.