These are just bits and pieces I've accumulated while looking for my Cox, Conklin, Smack lines.
1. Handy and Martha Smack, Memphis, Scotland County, Missouri had many children including Robert J and Cornelia "Nellie". They are listed in the 1850 census. By 1860 all children are living with other families.
2. 1920 Fed Census Robert J Smack living with his sister Nellie Cox in Watonga, Blaine County, Oklahoma.
3. 1930 Fed Census Watonga District 27 Blaine County, Oklahoma lists Abbie Jackson, 60, head of household; Robert Smack, 86, father; and M???? Conklin, 36, Son.
4. Robert Smack married Nancy Houchin 3 Aug 1865 Logan Co Illinois. Found information, but I have checked the 1880 Illinois Census, and they are there with the children. My family lines were all over Ohio, Illinois, and Nebraska, and everything seems to fit nicely.
5. NEMAH COUNTY HERALD SOUTH AUBURN, NE. 11/22/1895
'Mr. F,N, Conklin and Miss. Eva Smackwere united in marriage at Auburn... Th bride is a daughter of Robert Smack, two miles south of town and a young lady respected by everyone. The groom is nobody else but Friend Conklin, everybody knows him,he has lived in Johnson county for years, (Found information, not verified).
6. 1885 Nebraska State Census, Helena, Johnson County, Nebraska lists D Conklin 58 born in Penn, A Conklin 53 Penn, William 19 Penn, Friend 15 Penn, Floyd 13 Penn, Ella 2? Penn.
7. 1880 Federal Census Nebraska, Johnson County, Nemah Precinct lists Conklin, David C 53 born Penn Parents born NY, Almeda 45 wife born Penn parents born Conn with several children including William, Friend N, Floyd, and Ellen.
8. 1870 Federal Census Pennsylvania Wayne County, Salem lists these households: Conklin, Leonard 76 born in NY with Margaret 67 born in NY. Next household Conklin, David C 44, Almedia 36, other children including William 4 and Friend N 2/12, and Dickens, Sarah 70 born in Conn. Probably his parents next door and her mother living with them.
Hope this helps. I have a few snapshots of some of the Smacks.