[Snowyman]

I’m still trying to figure out where exactly this Lower Canada is/was/might have been.

“Beginning in 1610, Lower Canada, a new British colony, flew Great Britain’s Union Jack, or Royal Union Flag.”

[Squawk 8888]

Lower Canada was what is now Québec while Upper Canada is now Ontario. The designations were based on their relative positions along the St. Lawrence River.

[Don W]

Upper Canada=Ontario (headwaters of the St. Lawrence: Up river=upper)
Lower Canada=Quebec {”new” colony after the war with France}(run of the river: downstream=lower)

[oldweesie]

The names Lower and Upper Canada derive from their relative position along the Great Lakes/St. Lawrence River system. Lower Canada is downstream and, for the most part, is now Quebec. Upper Canada is upstream and is more or less now Ontario.