I can see her in one tree on Ancestry :
Ann Campbell, Fox, Mckenna 1840-1904
Born 1840 at Coalisland, Tyrone, Ireland
Died 5th May 1904, Shamble Lane, Dungannon, Tyrone, Northern Ireland
Her place and date of birth are linked to one of her son's birth information, and she married Peter Fox (not shown) then Peter McKenna in 1870. First Fox child in 1861, Peter Fox died 1869, married Peter McKenna in Dunganoon in 1870.
Tried to follow the tree but some of the links do not make sense, her death is linked to this:
Anne Fox Born about 1828 Death registered 1904 September quarter aged 76 at Dungannon
Ancestry is now trying to make me log into the USA site, and having problems. It is stuck in a loop - a bit like that tree.