My second great-grandparents Elise [Schmitt] and Jacob Mueller were married by a Justice of the Peace in Chicago in November of 1874. Elise grew up in the Catholic faith, but she may have left the church.
I haven’t had any luck connecting Jacob or Elise with a church, so I’ve starting looking into the churches attended by those around them.
It’s possible Elise and her brother or sister [who both lived nearby with their spouses] attended the same church.
According to Elise’s brother John Schmitt’s obituary, he attended Daylight Church.
According to Elise’s sister Anna Plum’s obituary, she attended the People’s Liberal Church.
These don’t appear to be your run of the mill religious organizations and I’m having a difficult time finding extant records from either church.