Jonathan came to Morgan County, Ohio with his parents from Loudoun County, Virginia when he was seven years old. At the age of 15, Jonathan was apprenticed to the trade of carpenter and joiner at which he served for six years. At the age of twenty-one he started looking for work and ended up in Muskinghum County, Ohio where he met Frederick Henderson. After two years he had saved $200.00 and he and Frederick Henderson started for Findlay where Mr. Henderson had already purchased property. On the 18th of October 1831 they left Blue Rock Twp., Muskinghum County, OH. It took them ten days to make the trip, having endured many hardships along the way. They both settled in Findlay. In 1832 Jonathan Parker, William Tayler and Frederick Henderson were contracted to build the first court house. In 1835 Governor Lucas called troops together to protect the northern boundary of Ohio against Michigan claims (the Toledo War) and the company recruited in Findlay was commanded by Jonathan Parker. The controversy between the two states, however, was settled amicably, without resort to arms. Jonathan constructed the first steam saw mill on the north bank of the river in 1846 which was in successful operation until March 10, 1874 when it was completely wrecked by its boiler exploding. In 1857 he erected a combined saw and grist mill in the southwest part of the village on Lincoln Street which his son, John, later took over. Jonathan was an active Whig and a staunch Republican and united with the Methodist Church in 1842. Jonathan was possibly a conductor with the Underground RR. He was very active in the Hancock County Pioneer Association. There is no death record or estate for him in the Hancock County Probate Court.