Geography · Great Lakes · Map

How much of Lake Superior is in Canada? 35.8%

About a third of Lake Superior is in Canada: 35.8% of its surface, 29,460 of 82,311 km². The United States holds the other 64.2%. The split is measured along the International Boundary Commission's surveyed border.

Published 9 Oct 2026 · Open Data Canada Sources International Boundary Commission · Natural Earth · NOAA GLERL

82,311 km²total surface, first-largest of the five Great Lakes
35.8%in Canada (29,460 km²), 4th of five by Canadian share
64.2%in the United States (52,851 km²)
32.9%of all Great Lakes surface Canada holds (89,664 km²)

Map of Lake Superior split along the Canada–U.S. boundary, shown as a dashed line. The Canadian part, 29,460 km² or 35.8%, is red; the U.S. part, 52,851 km², is navy.

Surface area on each side of the surveyed border. Source: International Boundary Commission boundary v1.3; Natural Earth lake outlines; ODC calculation in an equal-area projection (EPSG:3174).

Canada holds 36% of Lake Superior

Superior is the largest Great Lake (82,311 km²) but has the smallest Canadian share of the four lakes Canada shares. Even so, Canada's piece, 29,460 km², is larger than all of Lake Erie (25,736 km²) and Lake Ontario (19,464 km²). Superior is also the only Great Lake running low this year: its provisional September 2026 level was 5.4 cm below its 1918–2025 September average (tied 70th-highest of 109 Septembers).

All five lakes compared

Lake	Canada share	Canada km²	U.S. km²	Total km²
Superior	35.8%	29,460	52,851	82,311
Michigan	0.0%	0	57,541	57,541
Huron	61.0%	36,550	23,387	59,937
Erie	50.5%	13,002	12,734	25,736
Ontario	54.7%	10,653	8,810	19,464
All five lakes	36.6%	89,664	155,323	244,987

Common questions

How much of Lake Superior is in Canada? About a third. Canada holds 35.8% of Lake Superior's surface, 29,460 of 82,311 km², and the United States holds the other 64.2%.

Is more of Lake Superior in Canada or the US? The United States. It holds 52,851 km² (64.2%) to Canada's 29,460 km².

Which province borders Lake Superior? Ontario. The Canadian side of every shared Great Lake is in Ontario.

Sources

International Boundary Commission, official digital boundary shapefile v1.3 (labelled for mapping use only, not to define the boundary)
Natural Earth, 10m lake outlines
NOAA Great Lakes Environmental Research Laboratory, lake-wide monthly water levels 1918–2026. September 2026 values are provisional; see 2026 Great Lakes water levels.

Method Each lake outline was cut along the surveyed boundary and measured in EPSG:3174 (NAD83 / Great Lakes and St. Lawrence Albers), an equal-area projection. Figures are the published split from our Great Lakes map.

Limits

Surface area only. The boundary data and lake outlines give no depth, water volume or per-country shoreline, so this page does not say how much of the lake's water each country holds.

All five lakes on one map: How much of each Great Lake is in Canada?

Other lakes: Lake Michigan · Lake Huron · Lake Erie · Lake Ontario

How much of Lake Superior is in Canada? 35.8%

Canada holds 36% of Lake Superior

All five lakes compared

Common questions

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