Here is some information posted on Ancestry.com that I think may be about our common ancestor, John Justis:
Background on John Justis For many years descendants of John Justis , a Revolutionary War veteran from Delaware have tried unsuccesfully to determine his parentage, ancestry and date and place of birth.
Census records seem to indicate that John and his family must have moved alot after the Revolution since the birthplaces of his children were given as Delaware, Maryland, Pennsylvania and Ohio. The biography of one son mentions that the family went to "Monongahela" before coming West. the 1817 Hamilton County census lists a John Justis family, but it cannot be proven that this is the John from Delaware.
All that is definitely known about John is that he was born c1750, probably in Delaware and was married in 1784 in New Castle Co., Delaware to Susanna Tourneur, daughter of Peter Tourneur (1732-1777) and his wife, elizabeth Grevenraet (1739-1779). although Susanna was a minor around 19 at the time of the marriage, Delaware researchers have been unable to find any record of consent to marry or transfer of her property to her husband. The Tourneuer family was apparently well-to-do.
Since John was married in Delaware and since they named their first son, morton Justis, it is highly likely that John came from the Delaware Justis family, originally named Gustafsson, which came there around 1626 with a large gruop of Swedes. This Justis family intermarried with a Morton family in the 1700's. However researchers have been unable to find records connection John with the earlier Morton Justis because records are so incomplete.