He is married to Barbara DETRICK.
They got married on March 4, 1817 at Shenandoah, Virginia, Verenigde Staten, he was 25 years old.Source 2
Child(ren):
Shenandoah Co. Marriage Records list the marriage of John Ohmart to Barbara Dederich on 4 Mar 1817. I have used the spelling Detrick because that is how most of the family which migrated to OH ended up spelling it. Leona Betteridge lists as probable children for John: "Jessie, George, and Barbara who married George Keifer." However, Clark County marriage records list the marriage of "Mrs. Barbara Ohmart" to George Keifer on 22 Mar 1827. John is unlikely to have a daughter born early enough to be marrying in 1827, and the "Mrs." would seem to indicate that this Barbara was a widow. She was most likely John's widow, born Barbara Detrick, as John died in 1825.