My great-grandmother was named Wilhelmina Krohn, but she was married to a John Greuel Sr.They lived in the Milwaukee area in the late 1890's and early 1900's. My grandfather is one of their sons, born Nov 24 1894. The rest of the siblings included Edwin, Elmer, Johnny (Jr), Harvey and Edna. Not sure if this fits your timeframe. I can get no further back than this in my search for Greuels or Krohns.