Individual Details

Agnes seemed to be still living with her mother in 1850.

1860 Census. Manchester/Bonhomme Twp. Fenton is the P.O.
Hh 124
Mary "Willson", age 57, b. KY.
Nancy, 37, b. KY
Agnes E. age 27, b. KY
Ann E., age 19, b. MO [this would seem to be the daughter called Polly in 1850, but I can't explain the name change nor the age.... It is also possible Polly was already married. There was a granddaughter, daughter of Benjamin but of this age and perhaps named Ann Eliza, but she was counted in her father's household in Lafayette Co]
Albert McCane, age 14, b. MO

I found the following marriage but have not found the couple in a census.
Agnes E. Wilson married James McFarland, 8 Mar 1861, St. Louis, MO
[St. Louis, Mo Marriages, 1804-76 - database on Ancestry.com]

Birth

Abt 1828

Saint Louis County, Missouri

Father	John Wilson (1785 - 1837)
Mother	Mary "Polly" Haden (1800 - 1867)
Sibling	Benjamin H. Wilson (1819 - )
Sibling	Lycurgus Wilson (1821 - 1886)
Sibling	Nancy Wilson (1822 - )
Sibling	Leonidas Wilson (1824 - 1887)
Sibling	Sarah "Sally" Wilson (1831 - )
Sibling	Mariah Jane Wilson (1834 - 1865)
Sibling	Mary "Polly" Wilson (1837 - )