Do you know her relationship with anyone, like a spouse or one of her parents? Where did she live last, (country, state) do you know?
There are several Jennie Manley's in ancestry.com public trees in the 1870s and a couple of Jennie Marksons. One Jennie Markson was supposedly born in Poland in 1878, another was born in Russia in 1868. Most of the Jennie Mansleys were born in the USA in one state or another.