Individual Details

1850 Breckinridge Co., KY, census, p.118A, District No. 1, Aug. _, 1850, Thos. T. Crittenden:
329/330, ISAAC H. THOMAS, 29 M, farmer, $300 real, MO;
Mary A., 21 F, KY;
Susan E., 4 F, KY; William H., 3 M, KY; Alfried [sic], 2 M, KY.

Apparently both parents died prior to 1860. Perhaps two more children. Sarah Elizabeth, b. 1850, d. 1855 and wouldn't appear in a census. FamilySearch has exact dates but I found no burial information. A daughter Mary Hardin Thomas was born 1 Feb 1853, died as Mary Norris, 4 Jan 1918, Manchester, Delaware, Iowa, stating her parents were Isaac Thomas and Mary Miller. I have no idea where she was for the 1860 census!

Isaac's children were with their grandmother in 1860.
What happened to their parents?
1860 Linn Co., IA, census, p.296, Otter Creek Twp., P.O. Lafayette, Aug. 8, 1860, Saml. W. Durham: Hh 2110/2133,
ELIZABETH THOMAS, 63 F, $300 personal, MD;
Wallace, 21 M, $1260 real, $395 personal, KY;
Susan E., 14 F, KY; William H., 12 M, KY; Alfred J., 11 M, KY.

1870 Linn Co., IA, census, pp.425B-426A, Otter Creek Twp., P.O. Lafayette, July 20, 1870, C.A. Hesston: Hh 185/185,
FRED [sic] THOMAS, 40 F W, keeping house, KY;
Wm., 22 M W, farmer, $350 personal, KY;
Alfred, 21 M W, farmer, KY.

1880 census, William and Alfred have not been located

Birth	25 Jul 1821	Hardin County, Kentucky
Marriage	16 Jun 1845	Mary Ann Miller
Death	12 Jan 1852

Spouse	Mary Ann Miller (1828 - )
Child	William Henry Thomas (1847 - 1921)

Father	Joseph Hardin Thomas (1794 - 1850)
Mother	Elizabeth Goldsberry (1796 - 1870)