I Have Hit a Dead End Trying to Research My Gggrandfather David Casey

I have hit a dead end trying to research my GGgrandfather, David Casey
b.1818-1820 Grayson County Kentucky. Married to Eliza Pearl, Children
William T, James H.,Nicholas H.,Mary E., Sarah J., Margaret M., GeorgeR., Nancy A., and possibly Ada. Only info I can locate is Census.