It sounds like, from what I have found, that he may have come from Virginia or Pennsylvania????
I wrote this:
(The family apparently meandered from Pennsylvania to West Virginia to Virginia to Illinois).
James Garretson traveled with the Revolutionary War soldiers, ran for magistrate, and appeared on the militia list. James was one of General George Rogers Clark’s soldiers in Illinois and Indiana. After the Revolution, in 1781, many Virginians who had served with George Rogers Clark came to Monroe County area and received land grants there in that wild land for their services.James had gone home to Virginia and with others, gathered their families, and rafted from Ohio County (Wheeling) West Virginia down the Ohio River and settled in St. Clair County on a farm near Bellefontaine, a mile northeast of the present town of Waterloo in 1782; later their part became Monroe County. Illinois was a county of Virginia immediately after the Revolutionary War. The first five Americans - Virginia soldiers called “long knives” took their military pay in Illinois land; they were Shadrach Bond, Capt. James Moore, Robert Kidd, James Garretson, and Larkin Rutherford.
If you have any other ideas on where he was born, I would appreciate the information, firstname.lastname@example.org