Pomerania
My Born great-grandparents emigrated from Pomerania (German Pommern), a strongly Protestant, Lutheran province of the German kingdom of Prussia, to North Dakota in the late 1800's.
Following World War I, Prussia became part of the Weimar Republic as a free state in 1919; it was abolished as a state by the Nazis in 1934 and was not re-established by the Allies after World War II. Parts of Prussia, including eastern Pomerania where my ancestors lived, were given to Poland at that time.
This map shows the province of Pomerania. The purple/pink line represents the present-day border between Germany on the left and Poland on the right. The home of the Borns was the village Shoenhagen, which is not shown on the above map. It is six miles southwest of the city of Naugard, shown a little bit below the center of the map as both Naugard (the German name) and Nowogard (the present-day Polish name).
My forebears in Prussia, disturbed by the increasing militarism of the government headed by Otto von Bismarck, quietly made the decision to emigrate to America in the 1870's and 1880's. Once here, they lived for a time in Wisconsin before moving on to northeastern North Dakota when they heard there was good farmland available there for homesteading.