A simple history lesson is one my Mother (who immigrated in 1913) told me....from 1772 until 1918 there was no country known as Poland.As the result of various wars, Poland was partitioned in three and ruled by Russia, Germany (Prussia) and Austria (Galicia).Those living in these partitions were required to identify themseles as being Russian, German or Austrian.That explains why on U.S. census records and manifests of 1900 and 1910 you will note they are identified as Russian, German or Austrian.
The largest wave of Polis immigration to America occurred in the early 20th century. Initially, Polis immigrants came mainly from the German secion of the partition, where they were targeted by Bismark's anti-Catholic drive.After 1900, German Poles were outnumbered by immirants from Austrian and Russian Poland.
Some argue that many of the immigrants did not plan to remain permanently and become "Americanized."Instead they came temporarily to earn money, invest in property and wait for the right opportunity to return to Poland.The coming of World War I in 1914 made return almost impossible.
Below is a brief, but more "formal" history lesson:
Between 1772 and 1795 the entire territory of the Kingdom of Poland was divided between Prussia, Austria and Russia. During those so-called Partitions of Poland, Prussia acquired the western regions of Poland, esp. those, which were later renamed to West Prussia (formerly Royal Prussia) and Province of Posen (the area around Poznan, the Polish name being Wielkopolska, i.e. Greater Poland). The southern Polish territories around Kraków and Lwów were incorporated into the Austrian Empire and renamed "Galicia". The central and eastern provinces of Poland were taken over by the Russian Empire. Only during a short period when Napoleon Bonaparte conquered Central Europe, he restored Poland as a Duchy of Warsaw, dependent on himself, consisting of the territories Prussia and Austria had annexed in 1793-95.
After Napoleon's fall, the situation was finally resolved in 1815. The victorious Russia took control over most of the Duchy of Warsaw. The Tzars gave it relatively much autonomy and created the new Kingdom of Poland there (but dependent on Russia) whereas the former eastern parts of Poland were directly incorporated into the Empire (and the populace of the Byzantine Catholics living there was forced to "convert" to Eastern Orthodox). The boundaries fixed in 1815 were stable during the next century but many other things changed. The 19th century was the time of industrial development and massive migrations. The Polish provinces under Prussian government were slowly germanized as more and more Germans settled there. Several attempts to regain independence were made by Poles, but all the uprisings against Russia, Prussia and Austria were bloodily suppressed. That was one of the reasons why in the last three decades of the 19th century more than a million people emmigrated from Poland, mostly to North America.
The First World War was a catastophe for all the Empires that had once divided Poland. An independent Republic of Poland was restored. Most of the 19th century Kingdom of Poland, the whole Galicia and most of the former Prussian provinces of West Prussia and Posen together with some areas of present-day Belarus, Lithuania and Ukraine constituted Poland between the Wars. Most German inhabitants of the former Prussian provinces emigrated to Germany.