Kupfer Family Genealogy Forum
I think it's interesting that your relative moved to Savanna, Carroll Co., Illinois. My great-grandparents, Christian TOEPFER and Sophia KUPFER were married in Carroll Co. 15 Apr. 1889. The TOEPFER family farm was just north of Mount Carroll (the county seat), in Jo Daviess County, Illinois. Mount Carroll in only about 9 miles from Savanna.
Sophia was born in Germany in July 1871. I don't know of any of Sophia's siblings except for a half-sister, Margaret. I know she had brothers, since they arranged her marriage before she came to the US. [ ! ] I think there's a possible connection here.
Also: I have found several KUPFERS in the online index of Naturalizations done in Carroll Co. from the Carroll County Genealogical Society at: http://www.internetni.com/~ahaliotis/courtnat.htm