Alt birthdate: 25 July 1844
Isaac was an orphan (son of Isaac Alldredge Sr, and Mary Brown.) At the time of the 1850 federal census he and his brother Parsons were living in the household of their half brother Richard Wilks at Perry, Pike County, Illinois. Isaac crossed the plains with his maternal uncle, John Brown in 1853. At the time of the 1856 Territorial census of Utah Isaac was in Lehi and he was baptized thereon 12 April 1856. His birth date is confirmed by Lehi Ward records on the day he was rebaptized on 16 February 1863. His death date is confirmed by his death certificate.