The map above shows Montana and Ontario side by side at exactly the same scale, using equal-area projections, so their true relative sizes are preserved.
Montana vs Ontario Geography
Land area: Montana has a land area of 145,550 square miles (376,973 km²), while Ontario has 354,342 square miles (917,741 km²). Ontario's land area is 2.4 times (143%) larger than Montana's.
Total area: Montana: 147,043 square miles (380,840 km²) vs Ontario: 415,598 square miles (1,076,395 km²), including inland and coastal water. Ontario's total area is 2.8 times (183%) larger than Montana's.
Length: Montana is 319 miles (514 km) long from north to south; Ontario is 1,085 miles (1,747 km). Ontario's north-south length is 3.4 times (240%) longer than Montana's.
Width: Montana spans 607 miles (976 km) east to west; Ontario spans 1,013 miles (1,630 km). Ontario's east-west width is 1.7 times (67%) wider than Montana's.
Highest point: Montana's highest point is Granite Peak at 12,767 feet (3,891 m); Ontario's is Ishpatina Ridge at 2,274 feet (693 m). Granite Peak is 10,493 feet higher than Ishpatina Ridge.
Lowest point: Montana's lowest point is Kootenai River at 1,805 feet; Ontario's is Hudson Bay at 0 feet. Ontario's lowest point is 1,805 feet lower.
Montana vs Ontario Population and History
Population: Montana has a population of 1,137,233 (2024), while Ontario has 16,136,480 (2026). Ontario's population is 14.2 times larger than Montana's.
Population density: Montana: 7.8 people per square mile vs Ontario: 45.5. Ontario's population density is 5.8 times (483%) higher than Montana's.
Biggest city: Montana's biggest city is Billings with 121,483 people; Ontario's is Toronto with 2,794,356. Toronto's population is 23.0 times larger than Billings'.
Largest metro area: Montana's largest metropolitan area is Billings, MT metro area (192,531 people) vs Ontario's Toronto CMA (6,202,225). Toronto CMA's population is 32.2 times larger than Billings, MT metro area's.
History: Montana: Admitted to the Union on November 8, 1889, as the 41st state. Ontario: Joined Confederation on July 1, 1867, as one of the four founding provinces. In its current form, Ontario is the older of the two by 22 years.
Montana vs Ontario Economy
GDP: Montana's GDP is $78.4 billion (2024) vs Ontario's $873.9 billion. Ontario's economic output is 11.1 times larger than Montana's.
GDP per capita: Montana: $68,975 per person vs Ontario: $54,132. Montana's GDP per capita is 1.3 times (27%) higher than Ontario's.
Official Websites
Montana official website · Ontario official website
More Size Comparisons
All Montana size comparisons · All Ontario 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.