John S. Shanklin married Sarah Elizabeth McClelland, a cousin on his mother’s side of the family, in 1849 and the couple had 3 children: James (1850-1906), Mary J. Kirchoff (1852-1939), and Margaret Beardslee (b.1854). In 1857 the Shanklin family was farming 294 acres in Southfield Twp. John’s widowed mother, Sarah C., was living with his family.
On February 27, 1864 John S. Shanklin enlisted as a private in the 2nd MI Infantry, Company E at age 41 in Oakland, MI. He was captured and imprisoned in Danville Prison. John S. Shanklin died of disease as a POW on August 27, 1864, exactly 6 months after he enlisted. He is buried in Danville National Cemetery, plot A 13.