The map above shows Guam and Ontario side by side at exactly the same scale, using equal-area projections, so their true relative sizes are preserved.
Guam vs Ontario Geography
Land area: Guam has a land area of 210 square miles (544 km²), while Ontario has 354,342 square miles (917,741 km²). Ontario's land area is 1,687.0 times larger than Guam's.
Total area: Guam: 210 square miles (544 km²) vs Ontario: 415,598 square miles (1,076,395 km²), including inland and coastal water. Ontario's total area is 1,978.7 times larger than Guam's.
Length: Guam is 27 miles (43 km) long from north to south; Ontario is 1,085 miles (1,747 km). Ontario's north-south length is 40.2 times longer than Guam's.
Width: Guam spans 22 miles (35 km) east to west; Ontario spans 1,013 miles (1,630 km). Ontario's east-west width is 46.0 times wider than Guam's.
Highest point: Guam's highest point is Mount Lamlam at 1,332 feet (406 m); Ontario's is Ishpatina Ridge at 2,274 feet (693 m). Ishpatina Ridge is 942 feet higher than Mount Lamlam.
Lowest point: Guam's lowest point is Pacific Ocean at 0 feet; Ontario's is Hudson Bay at 0 feet. Both lowest points are at or near sea level.
Guam vs Ontario Population and History
Population: Guam has a population of 153,836 (2020), while Ontario has 16,136,480 (2026). Ontario's population is 104.9 times larger than Guam's.
Population density: Guam: 732.6 people per square mile vs Ontario: 45.5. Guam's population density is 16.1 times higher than Ontario's.
History: Guam: A US territory since 1898. 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 31 years.
Official Websites
Guam official website · Ontario official website
More Size Comparisons
All Guam 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.