I wonder if anyone can help me learn more about some of my ancestors who came from Schwyz to the U.S.

Catherine Holdener (except I've sometimes seen it written Holdenener or Holdenner) married Louis Fassler. They immigrated to the US, settling in Missouri, they were my great-grandparents and I know little or nothing about them. They spoke German when they arrived and were members of the Catholic church. I believe that Catherine's father was named John the Baptist Holdener [Johann]

Any information or pointers or tips would be appreciated.

Adrien Taylor
Boise, Idaho