I am also researching the Thrap family. And my records show that Sarah (Sally) Thrap b. 20 Jan 1787 in Gallows Hills, Baltimore County, Maryland was born to John Thrap b. 1761 in Gallowa Hills, Maryland d. 1845 in Perry or Muskingham County, Ohio. John was the son of Robert Thrap b. 1728 in Joppa, Hartford County, Maryland and Elizabeth Hilton b. 1743 in Hartford County, Maryland. Which makes Robert Thrap and Elizabeth Hilton her grandparents and not her parents.