Answer:
Northern & Western Europe, specifically Britain & Ireland.
Explanation:
Britain's reasons for immigration was similar as before, with people trying to find a better life style in the still relatively "new world". They hoped to be able to restart their life's there.
As for Ireland, their main reason for immigrating was the potato famine, in which their crops failed, and there was a mass starvation. Those who survived and who could, moved to the US in hopes of using the rich soil to sustain them there.
British who moved was to have a change of life style, while for Ireland, it was almost a necessity for survival.