Reservoir
Lake St. John
Natural Earth’s outline of Lake St. John measures about 1,050 km² (406 mi²), the 94th largest of the 104 lakes on sizeversus, and about the same size as São Tomé and Príncipe.
20 km
- Lake St. John
- São Tomé and Príncipe
The numbers
- 1,050km²Area, measured406 mi² · Natural Earth outline
- 1,000km²Area, publishedWikidata · 4.9% below our measure
- 63mGreatest depthWikidata
- 96mAbove 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%.
What the numbers say about Lake St. John
- The Caspian Sea (called a sea or a lake, depending on the definition), the largest of the 104 lakes ranked on sizeversus, is 361× the size of Lake St. John; Lake St. John ranks 94th.
- Lake St. John sits between Lake Amadeus (1,070 km²) and O'Higgins/San Martín Lake (1,050 km²) in the ranking.
- It is a reservoir, made by a dam, and the 13th largest of the 14 reservoirs in this ranking.
- Counted as a country, Lake St. John would be larger than 35 of the 212 countries listed on sizeversus and would rank 178th by area, between the Comoros (1,670 km²) and São Tomé and Príncipe (1,040 km²).
- It is larger than 1 of the 51 US states and districts (the biggest of them is Washington, D.C., 162 km²) and smaller than 50.
- It is smaller than every one of the 31 provinces and regions of China.
- The closest US state is Rhode Island (2,830 km²): Lake St. John is 37% of the size of Rhode Island.
- Wikidata records a greatest depth of 63 m.
- Its surface lies about 96 m above sea level (Wikidata).
- On a standard web map (Web Mercator), a place at 49°N is drawn about 2.3× too large in area, so Lake St. John looks bigger there than it is.
- Laid out flat, Lake St. John stretches about 39 km north to south and 46 km east to west.
- Our measured 1,050 km² is 4.9% above Wikidata’s published figure of 1,000 km². Published areas of lakes and seas move with the water level and with what is counted, so a few percent is expected.
About the same size as
Countries
US states
On the shore
Natural Earth’s outlines of Canada contain or lie within 4 km of the outline of Lake St. John. 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 St. Johnthe name in this page’s titlesource: Wikidata’s English label
- Saint-Jeanalso calledsource: Natural Earth
- Lac Saint-Jeanalso calledsource: Natural Earth
Where Lake St. John ranks
Lake St. John is the 94th 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