Many German Americans can trace their family back to the Hessian mercenaries who fought for the British during the American Revolution. They saw what freedom is for the first time in their lives and liked what they saw, so they stayed behind.
German immigrants came from the Austrian Empire, Romania, and the United State. There were some who came from Canada and they were filled with fear of the northern climate, and the German government's opposition of emigration. For more information, check out http://esask.uregina.ca/entry/german_settlements.html.