Most of the immigrants to New England came in a 20 year time frame from 1620 to 1640. Although there were some other smaller migrations, apparently by the second decade of the 1800s almost all living New Englanders could trace a large percentage of their ancestry back to the original group of 25,000 who came in the great migration.
The Mid Atlantic and South had constant immigration after 1607. We are lucky to be in New England where we can trace our ancestors with less difficulty.