I have a Lockhart family in PA prior to 1800 and have encountered various spellings. Josiah Lockhart and his brothers Samuel and Robert lived in Lancaster, Pennsylvania. I have record of Josiah in PA as early as 1763 when he applied for a license as an Indian trader. Robert and Samuel I know both served in the Revolutionary War. I need to check and see if I have anywhere that Josiah did also.
Josiah married Esther McClure daughter of William McClure from a neighboring county (don't remember which at the moment). He had one son, Josiah Lockhart, still alive in 1809 when Josiah Sr. wrote his will and died. Esther was perhaps already dead at that point because there is no mention of her in the will. She was mentioned, however, in the will of her nephew Robert Lockhart (not the brother of Josiah but his nephew, have not established who his father was, though I suspect it was Robert.) Josiah left land to the English Presbyterian Church. In addition Robert, his nephew, had a sister, Margaret Lockhart who was unmarried when he wrote his will in 1804. He does not mention a wife or children, parents or other siblings besides Margaret. He does include aunts, uncles, cousins, and a grandmother. I have more information on all those folks from the will I managed to locate.Josiah also mentions a nephew, Thomas Lockhart, of County Tyrone, Ireland. Josiah's brother and Robert's uncle, Samuel Lockhart is mentioned in both wills, living in Frederick County, Virginia in 1804 (which is where his brother Robert lived - my ancestor, as I believe he is the same Robert Lockhart who married Margery Denny in 1778, widow of James Wilson).