The 1850 Shelby Co. KY census has W. Dunnigan (age 40, m, farmer, b. NC), wife Sophia (39, f, KY), Howard (16, m, KY), James (14, m, KY), Nancy (11, f, KY), Henry C. (5, m, KY), Olive (4, f, KY), Harrison (1, m, KY).
I believe W. Dunnigan, born abt. 1810, must have died before 1865.A book of Shelby Co. marriages had this listing for his daughter Olive:William Hammond of Shelby, age 30, 2nd marriage, farmer, b. Shelby; Father b. KY; Mother b. VA; and Olive Catharine Dunnigan of Shelby, age 19, 1st marriage, b. Shelby; dau. of Sophia Dunnigan b. KY; Father b. KY; married 26 Jan 1865.
From what I've been able to find online, Sophia remarried to a George Patterson, b. NC.I think Henry C. Dunigan died 6/19/1920 and James M. Dunigan died 11/7/1911, both in Shelby Co. KY.
Olive Catharine Dunnigan Hammond would be my gg grandmother.