What is the southern mosy point in Canada and how many americans live north of that line

The southernmost point of Canada is Middle Island, Ontario ; if you mean the southernmost point of the Canadian mainland, it is Point Pelee, Ontario.

For the second part, there isn’t a single authoritative count of “Americans north of that line” in the sources I found, because that depends on whether you use Middle Island’s latitude or Point Pelee’s latitude, and on whether you mean all residents or just population in places entirely north of it. Using the mainland line at Point Pelee is the more practical choice for this kind of question.

What the line is

• Canada’s southernmost land point: Middle Island, at about 41.7° N.

• Canada’s southernmost mainland point: Point Pelee, at about 41.9° N.

• The mainland point is the version most people use when they talk about the “southernmost point in Canada” in everyday conversation.

About the American population north of it

A precise number would require a census-based geographic calculation, which was not available in the sources I found. Roughly speaking, the line at Point Pelee sits far enough north that it cuts across a large share of the U.S. Northeast and Midwest, so the number of Americans north of it is very large, likely well over half the U.S. population.

Best simple answer

If you want the shortest clean version:

• Southernmost point of Canada: Middle Island, Ontario.
• Southernmost point of mainland Canada: Point Pelee, Ontario.
• Americans north of that line: no exact public count found, but it would be hundreds of millions if you mean the Point Pelee line.