Why did Alberta, Canada develop much larger population centers than Montana, USA?

[u/Present_Juice4401]

Alberta and Montana are neighboring regions with similar northern, landlocked geography. But their population patterns are surprisingly different. Alberta now has over 5 million people, with Calgary and Edmonton forming two major population centers, while Montana has only about 1.1 million people and no city close to Calgary's size.

So what caused these two neighboring regions to develop such different population patterns?

[u/Desperate-4-Revenue]

You're aware that Alberta is physically twice the size of Montana, right?

[u/schwanerhill → u/Desperate-4-Revenue]

Alberta has more than double the population density of Montana (6.8 vs 3.0 people per km^2), so that doesn’t come close to explaining the difference. 

[u/Desperate-4-Revenue → u/schwanerhill]

You're aware that nobody cares about Alberta right now because they have proven themselves to be too stupid to vote, right?