I know your posting was a old one, but if you don't by know, Mary Cathrine Campbell,(wife of George G. Keller), was the daughter of Charles Campbell of Connecticutt and Barbara (Freed) Campbell of Virgina. She was born in Ohio and married in Fairfield County, Ohio. Most of their children were born in Fairfield, Ohio, At least one, James I believe was born in LaGrange County, Indiana. Sarah (child #5) was born in 1873 in Fairfield, Ohio and died the same year and is buried in Fairfield Co. Sam may have been born in Indiana, or in Branch Co., Michigan.
There is no relationship to the family of Louis Keller that I know of.