Parkhurst genealogy is my hobby. I believe that 95% of Parkhursts in the USA today can trace their Parkhurst descent from George-1 Parkhurst (1588-1675) of Ipswich, England and Watertown, MA. I have a data base with over 30,000 names in it. I try to connect Parkhursts to names in my data base and back to the above George-1 Parkhurst.
The Parkhurst fragment:
Daniel Parkhurst b 1724 in Chester Co., PA m 1745 Lydia unknown in Lancaster Co., PA
Samuel Parkhurst b 1746 m 1767 Sarah Reed
Jacob Parkhurst b 1772 m 1792 Ann Craft in Washington Co., PA
is a little mixed up. I think that it is the result of some creative genealogy. The Daniel who served in the Washington Co., PA Militia during the Revolutionary War was a son of Samuel's, not his father. Samuel's son, Jacob, in his "Sketches" said that his brother served as a scout with the rangers during the war. There is only one Daniel Parkhurst with Militia service in the Washington Co., PA records.
There are no records of Parkhursts in Chseter Co., PA or Lancaster Co., PA in the period before 1750.
I think someone found the service for a Daniel Parkhurst in Washington Co., PA and made him the father of Samuel and created a wife, Lydia, for him.
I have not found a marriage for the son, Daniel. The only Daniel taxed in Washington Co., PA was a single man.
Samuel Parkhurst (father of Jacob) married Sarah Gard in Morristown, Morris Co., NJ on 29 Jan 1761. Samuel met and married Sarah in Morristown and almost certainly was living there before his marriage. He probably was born and grew up with the other Parkhursts of Morristown. Samuel's birth is not in the surviving Morristown Church records. This is because the surviving records don't start until 1742. I believe that Samuel had a sister, Phebe, who also was born before the surviving records start.
While there is no proof that Samuel's parents were John and Mary, the weight of the available evidence makes it very likely that they were.
I have published a book on the first nine generations of Parkhursts from George-1 Parkhurst (1588-1675) of Ipswich, England and Watertown, MA. My book does not contain any additional information on the ancestry of Jacob Parkhurst than what is in the enclosed report. A few copies are still available at $40 postpaid.

Genealogically yours,

Peter G. Parkhurst