Thank you for your reply.
Louis Frederick would have been married to Anna in 1880 as the census records you found indicate. His first wife Mary Emma Collins died in 1867. Louis Frederick and Mary's son, Louis, would have been 16 at that time.
But then our sources differ. Louis, the son, married Nora Emma Roach on 30 Nov 1886 in St. Mary's Church in Champaign, Illinois. I have a photocopy of a newspaper article of the celebration of their 60th wedding anniversary. The two are buried in St. Mary's Cemetery in Champaign. Nora's parents were John & Sarah Roach who came from Ireland.
Louis and Nora are my mother's grandparents. She vaguely remembers attending the 60th wedding anniversary celebration.
Happy to compare notes.
Lisa