The map above shows Idaho and South Australia side by side at exactly the same scale, using equal-area projections, so their true relative sizes are preserved.
Idaho vs South Australia Geography
Land area: Idaho has a land area of 82,645 square miles (214,051 km²), while South Australia has 380,048 square miles (984,321 km²). South Australia's land area is 4.6 times (360%) larger than Idaho's.
Total area: Idaho: 83,569 square miles (216,441 km²) vs South Australia: 380,048 square miles (984,321 km²), including inland and coastal water. South Australia's total area is 4.5 times (355%) larger than Idaho's.
Length: Idaho is 483 miles (778 km) long from north to south; South Australia is 1,078 miles (1,735 km). South Australia's north-south length is 2.2 times (123%) longer than Idaho's.
Width: Idaho spans 352 miles (566 km) east to west; South Australia spans 825 miles (1,328 km). South Australia's east-west width is 2.3 times (134%) wider than Idaho's.
Highest point: Idaho's highest point is Borah Peak at 12,631 feet (3,850 m); South Australia's is Mount Woodroffe at 4,708 feet (1,435 m). Borah Peak is 7,923 feet higher than Mount Woodroffe.
Lowest point: Idaho's lowest point is Snake River at 718 feet; South Australia's is Lake Eyre at -49 feet. South Australia's lowest point is 767 feet lower.
Idaho vs South Australia Population and History
Population: Idaho has a population of 2,001,619 (2024), while South Australia has 1,908,182 (2025). Idaho's population is 1.0 times (5%) larger than South Australia's.
Population density: Idaho: 24.2 people per square mile vs South Australia: 5.0. Idaho's population density is 4.8 times (384%) higher than South Australia's.
Largest metro area: Idaho's largest metropolitan area is Boise City, ID metro area (845,877 people) vs South Australia's Greater Adelaide (1,491,015). Greater Adelaide's population is 1.8 times (76%) larger than Boise City, ID metro area's.
History: Idaho: Admitted to the Union on July 3, 1890, as the 43rd state. South Australia: Became an Australian state at Federation on January 1, 1901; founded as a colony in 1836. In its current form, Idaho is the older of the two by 11 years.
Idaho vs South Australia Economy
GDP: Idaho's GDP is $129.0 billion (2024) vs South Australia's $100.2 billion. Idaho's economic output is 1.3 times (29%) larger than South Australia's.
GDP per capita: Idaho: $64,457 per person vs South Australia: $52,511. Idaho's GDP per capita is 1.2 times (23%) higher than South Australia's.
Official Websites
Idaho official website · South Australia official website
More Size Comparisons
All Idaho size comparisons · All South Australia 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.