Isaac D. Conrad was the second of four known children of Johann Leonard (went by Leonard) Conrad (1787–1865) and his first known wife, Anna "Chaney" West (1786–1822), who married c1807 at presumably North Carolina. After Chaney died, Leonard remarried to Rebecca Lash (1806-1843) and had two known additional children.

Isaac married Sarah (went by Sally) Maria Shamel (1817–1905) on 07 Oct 1834 at Stokes (presumably in part that became Forsyth County) County, North Carolina. Isaac and Sarah were the parents of twelve known children, namely:

1. Louisa Conrad (1835-1850)
2. Celestia Delitha Conrad McKnight (1836–1919)
3. John Calvin Conrad (1838–1895)
4. Wesley Conrad (1840-1843)
5. Delphina Arenia Conrad (1842-1847)
6. Gideon Hill Conrad (1844–1886)
7. George Dallas Conrad (1847–1917)
8. Lewis Alexander Conrad (1849–1874)
9. Wilson Conrad (1850-???)
10. Augusta Maria Conrad Livengood (1852–1937)
11. Gertrude Conrad (1853–???)
12. Regina Matilda Conrad Norman (1853–1926)

In 1850 the parents, Celesta, Calvin, Gideon, George and Lewis were living at Forsyth County, North Carolina. In 1860 the parents, Calvin, Gideon, George, Lewis, Augusta, and Regina were living at Yadkin Township, Forsyth County, North Carolina. In 1870 the parents, Lewis, Gertrude and Regina were living at South Fork Township, Forsyth County, North Carolina. In 1880 the parents and "son" Wilson (where was he in 1860 and 1870?, was he really a son?) were living at South Fork Township, Forsyth County, North Carolina. In 1900 the widow Sarah was living with her grandson Luke Conrad, his family, and Luke's mother, Edna Conrad (widow of the son John Calvin Conrad), at South Fork Township, Forsyth County, North Carolina.

Links to Isaac's parents, wife, six of his twelve known children and all of his five known siblings and half-siblings are included below.