The Loppnows seem to almost all immigrated to America in the late 1800's.  The bulk seem to have settled in Wisconsin and others that came later crossed the river up into Minnesota.  There are two lines of Loppnows in Minnesota that I know of.  The town of origins for both of these lines was Wisbu, near Loppnow.  I believe the Wisconsin Loppnows originated from the same area. 

I will add more information as time goes by but wanted to get this map up, that I recently acquired.

Maps

Map showing the location of the town of Loppnow, now called Lopianow in Poland.  After World War II the Germans were forced from their land and the towns and villages renamed. The German cemetary at Loppnow/Lopianow has been bulldozed.