Lake
Lake Ontario
Natural Earth’s outline of Lake Ontario measures about 19,500 km² (7,520 mi²), the 13th largest of the 104 lakes on sizeversus, and about the same size as Fiji.
200 km
- Lake Ontario
- Fiji
The numbers
- 19,500km²Area, measured7,520 mi² · Natural Earth outline
- 18,500km²Area, publishedWikidata · 5.1% below our measure, flagged
- 244mGreatest depthaverage about 84.2 m
- 1,639km³VolumeWikidata
- 74mAbove sea levelSurface, Wikidata
The area is measured from the outline drawn above, on the WGS84 ellipsoid; the published figure is shown beside it, and a water body is kept only if the two are within 10%. This one is between 5% and 10% apart, so it is flagged and no comparison is built for it automatically.
What the numbers say about Lake Ontario
- The Caspian Sea (called a sea or a lake, depending on the definition), the largest of the 104 lakes ranked on sizeversus, is 19.5× the size of Lake Ontario; Lake Ontario ranks 13th.
- Lake Ontario sits between Lake Winnipeg (24,800 km²) and Lake Ladoga (17,700 km²) in the ranking.
- Counted as a country, Lake Ontario would be larger than 58 of the 212 countries listed on sizeversus and would rank 155th by area, between Slovenia (20,300 km²) and Fiji (18,900 km²).
- It is larger than 5 of the 51 US states and districts (the biggest of them is Hawaii, 16,800 km²) and smaller than 46.
- It is larger than 3 of the 31 provinces and regions of China (the biggest of them is Beijing, 16,300 km²) and smaller than 28.
- The closest US state is New Jersey (19,700 km²): Lake Ontario is about the same size as New Jersey.
- Wikidata records a greatest depth of 244 m; with its volume that gives an average depth of about 84 m.
- Wikidata records a volume of 1,639 km³. Poured over Belgium (30,700 km²), that water would stand 53 m deep.
- Its surface lies about 74 m above sea level (Wikidata).
- On a standard web map (Web Mercator), a place at 44°N is drawn about 1.9× too large in area, so Lake Ontario looks bigger there than it is.
- Laid out flat, Lake Ontario stretches about 147 km north to south and 321 km east to west.
- Our measured 19,500 km² is 5.1% above Wikidata’s published figure of 18,500 km². This difference is flagged for review: a lake’s outline may include islands or bays that the published figure leaves out, or the water level may differ. The outline is kept because it is within 10%, and this page is not matched automatically to any other.
About the same size as
Countries
On the shore
Natural Earth’s outlines of Canada and the United States contain or lie within 4 km of the outline of Lake Ontario. That is what its geometry says, and it is not a statement about who owns the water or where any border runs in it.
Names
- Lake Ontariothe name in this page’s titlesource: Wikidata’s English label
- Great Lakesalso calledsource: Natural Earth
- Ontarioalso calledsource: Natural Earth
Where Lake Ontario ranks
Lake Ontario is the 13th largest of the 104 lakes on sizeversus, ranked by measured area.
Share this outline
Sources and method
- Outline
- Natural Earth, 1:10m Lakes + Reservoirs, public domain (Lakes + Reservoirs). Outlines of lakes are drawn at 1:10 million.
- Boundary
- A lake or a sea has no legal boundary of its own. The outline is a cartographic one, and the page says so by showing the measured area beside the published one.
- Area basis
- Measured outline: computed on the WGS84 ellipsoid from the full-detail outline and shown rounded. Published figure: Wikidata (CC0), fetched 2026-11-11. An outline is kept within 10% of the published figure and matched to other places automatically within 5%.
- Depth, volume, height
- As recorded in Wikidata; a volume that cannot be right for the area and depth is left out.
- Shore
- Countries whose Natural Earth outline contains or comes close to the water's outline; computed, not a statement of ownership.
- Drawing
- Each outline is projected with an equal-area projection centred on its own centroid, so areas stay true and two can be laid over each other.
- Data built
- 2026-11-11