The red part of Canada should be "Loyalists" - british decendents + various elite / slave owners that moved north after American independance.

Very much not the same as US "midlands" in my opinion.

The criteria is dominant ancestry source. Loyalists generally came from the red area and dark green areas of the US, but that'd be confusing recursion if Canadian regions were defined as where in the US people came from vs US regions being defined by where in Europe they came from.