All I can suggest is that "MOHN" has a variant spelling of "MANN."The MANN families (in the 1700s) came from Germany to Pennsylvania.They would have come from the Rhine Valley.(I'm going way back.)My prime advice is search variant spellings. Many MANNS settled in Bucks County, PA.But it is a German name, and if your family came to the U.S in the 18th century, they would have gone to PA.To Bucks or Northampton County.