Just to clarify: are we asking why and when Europeans started moving to the Americas?

Maybe you could narrow it down to a particular century or country of origin?

One major factor in choice of immigration destination is the existence of a beachhead community. It's far easier to move someplace where there are at least a few people who speak your language or might have family ties.

For example, there is a significant Hmong population in Saint Paul Minnesota. They did not move there for the weather, nor even for the funnel cakes. Most chose that city because there was already a Hmong community there.