Re: Research - What is (a) Jockey Hollow?
Not a direct answer, but a couple of stories behind the name for places in PA and NY with the same appelation, from 19th century workks digitized in Google Books. I was hoping to find something there from one of the old County History books. Maybe I can get to the hard copies a little later.
Pennsylvania: https://www.google.com/books/edition/The_Old_Pike/Lc4xAQAAMAAJ?hl=en&gbpv=1&bsq=%22Jockey%20Hollow%22