The map above shows Ontario and South Australia side by side at exactly the same scale, using equal-area projections, so their true relative sizes are preserved.
Ontario vs South Australia Geography
Land area: Ontario has a land area of 354,342 square miles (917,741 km²), while South Australia has 380,048 square miles (984,321 km²). South Australia's land area is 1.1 times (7%) larger than Ontario's.
Total area: Ontario: 415,598 square miles (1,076,395 km²) vs South Australia: 380,048 square miles (984,321 km²), including inland and coastal water. Ontario's total area is 1.1 times (9%) larger than South Australia's.
Length: Ontario is 1,085 miles (1,747 km) long from north to south; South Australia is 1,078 miles (1,735 km). Ontario and South Australia have about the same north-south length.
Width: Ontario spans 1,013 miles (1,630 km) east to west; South Australia spans 825 miles (1,328 km). Ontario's east-west width is 1.2 times (23%) wider than South Australia's.
Highest point: Ontario's highest point is Ishpatina Ridge at 2,274 feet (693 m); South Australia's is Mount Woodroffe at 4,708 feet (1,435 m). Mount Woodroffe is 2,434 feet higher than Ishpatina Ridge.
Lowest point: Ontario's lowest point is Hudson Bay at 0 feet; South Australia's is Lake Eyre at -49 feet. South Australia's lowest point is 49 feet lower.
Ontario vs South Australia Population and History
Population: Ontario has a population of 16,136,480 (2026), while South Australia has 1,908,182 (2025). Ontario's population is 8.5 times (746%) larger than South Australia's.
Population density: Ontario: 45.5 people per square mile vs South Australia: 5.0. Ontario's population density is 9.1 times (810%) higher than South Australia's.
Largest metro area: Ontario's largest metropolitan area is Toronto CMA (6,202,225 people) vs South Australia's Greater Adelaide (1,491,015). Toronto CMA's population is 4.2 times (316%) larger than Greater Adelaide's.
History: Ontario: Joined Confederation on July 1, 1867, as one of the four founding provinces. South Australia: Became an Australian state at Federation on January 1, 1901; founded as a colony in 1836. In its current form, Ontario is the older of the two by 34 years.
Ontario vs South Australia Economy
GDP: Ontario's GDP is $873.9 billion (2024) vs South Australia's $100.2 billion. Ontario's economic output is 8.7 times (772%) larger than South Australia's.
GDP per capita: Ontario: $54,132 per person vs South Australia: $52,511. Ontario and South Australia have about the same GDP per capita.
Official Websites
Ontario official website · South Australia official website
More Size Comparisons
All Ontario 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.