I have Jehu R. Jackman b. 22 Oct 1835 Washington Co. PA d. 1869-only son of John Jackman & Deborah Stockdale, may have, repeat "may have", md. Mary Culbertson.
Another Jehu ca. 1790 PA d. 17 Dec 1876 buried Roscoe, Washington Twp. PA, farmer, parents William T. Jackman and Barbara Shively md. Millie b. ca. 1800 - had a son John H. ca. 1839.
Another Jehu b. ca, 1791 PA, farmer, 1870 census he was 79, Cannon Anne 27 keeping house (don't know if she was wife) children William 8, George W. 5, Aaron 43. Living near were
Simeon & Mary Jackman, James Jackman 60, S. T. & Florence, S. A. and Margaret Jackman Chester, & Benjamin Chester.
Hope this helps. None of them realate to my Jackmans.