The map above shows Montana and South Australia side by side at exactly the same scale, using equal-area projections, so their true relative sizes are preserved.
Montana vs South Australia Geography
Land area: Montana has a land area of 145,550 square miles (376,973 km²), while South Australia has 380,048 square miles (984,321 km²). South Australia's land area is 2.6 times (161%) larger than Montana's.
Total area: Montana: 147,043 square miles (380,840 km²) vs South Australia: 380,048 square miles (984,321 km²), including inland and coastal water. South Australia's total area is 2.6 times (158%) larger than Montana's.
Length: Montana is 319 miles (514 km) long from north to south; South Australia is 1,078 miles (1,735 km). South Australia's north-south length is 3.4 times (238%) longer than Montana's.
Width: Montana spans 607 miles (976 km) east to west; South Australia spans 825 miles (1,328 km). South Australia's east-west width is 1.4 times (36%) wider than Montana's.
Highest point: Montana's highest point is Granite Peak at 12,767 feet (3,891 m); South Australia's is Mount Woodroffe at 4,708 feet (1,435 m). Granite Peak is 8,059 feet higher than Mount Woodroffe.
Lowest point: Montana's lowest point is Kootenai River at 1,805 feet; South Australia's is Lake Eyre at -49 feet. South Australia's lowest point is 1,854 feet lower.
Montana vs South Australia Population and History
Population: Montana has a population of 1,137,233 (2024), while South Australia has 1,908,182 (2025). South Australia's population is 1.7 times (68%) larger than Montana's.
Population density: Montana: 7.8 people per square mile vs South Australia: 5.0. Montana's population density is 1.6 times (56%) higher than South Australia's.
Largest metro area: Montana's largest metropolitan area is Billings, MT metro area (192,531 people) vs South Australia's Greater Adelaide (1,491,015). Greater Adelaide's population is 7.7 times (674%) larger than Billings, MT metro area's.
History: Montana: Admitted to the Union on November 8, 1889, as the 41st state. South Australia: Became an Australian state at Federation on January 1, 1901; founded as a colony in 1836. In its current form, Montana is the older of the two by 12 years.
Montana vs South Australia Economy
GDP: Montana's GDP is $78.4 billion (2024) vs South Australia's $100.2 billion. South Australia's economic output is 1.3 times (28%) larger than Montana's.
GDP per capita: Montana: $68,975 per person vs South Australia: $52,511. Montana's GDP per capita is 1.3 times (31%) higher than South Australia's.
Official Websites
Montana official website · South Australia official website
More Size Comparisons
All Montana 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.