Interesting! I have the following entry for Isaiah, s/o Levi and Mary DAVIS DUNGAN , but without the birthdate you give. If your birthdate is right then the marriage/children I have cannot be right! What is your source for the birthdate? Maybe there is an Isaiah we didn't know about!!
5Isaiah b.1764 Beaver Co PA, d.1/15/1856 McDonough Co IL, m1.1785 Eleanor JONES in Beaver Co, PA; listed 1805 with brother Levi; m2. Ahiu/Ann (in some accounts) UNKNOWN b.abt 1776 listed in 1850 Nobles Co, IND census as DANGAN with female Ahiu age 74. Held land in Washington Com PA 1/22/1785 with James. Moved to IND abt 1802. Isaiah was farmer and stock breeder. CHm1: 6Unknown b.abt 1788 6Mariah b.1790 Beaver Co, PA, m.11/7/1815 Fayette Co OH William J. MURRAY or BLACK 6Nancy b.1793 Beaver Co, PA, m1. WILLIAMS, m2. George NOBLE 6Samuel H. b.12/22/1800 Beaver Co, PA, d.4/21/1888 Harrison Co IA, m1.Sarah ROEBUCK; m2.7/25/1850 IN, OH Nancy Ann ARMSTRONG b.6/25 or 12/19/1805 OH (her m1. to Richard VAN ARSDOL/VANASDALL), m3.8/27/1858 Shelby IA Jane Bell FOUT/S b.9/26/1818 OH, d.3/21/1895 Harrison IA, brd Manteno Cem Shelby IA 6David Jones/D.J. b.1814 OH, d.1903 COL m.10/7/1834 Elkhart IN Mary BOLES b.1816 OH, d.1884 Andrew Co MO, listed in Nobles Co, IND 1850 census as DANGAN, also lived McDonough Co IL, Blue Earth Co MN and Andrew Co MO 6Rebecca b.abt 1816 6Unknown child, b.abt 1818, died young