A note on Findagrave.com says she was probably born in what is now Berkeley Co., WV, and what was then Frederick Co., VA.

Nancy Ann Morgan, the eldest child of Zackquill Morgan & his first wife, was 13 years old when the family moved to the Morgantown area. She married John Pierpont when she was 24 - he was much older (as old as her father). He died in 1796; sometime before 1802 she married William Stephenson. (Chapter XIV) [French Morgan, A History and Genealogy of the Family of Col. Morgan Morgan, The First White Settler of the State of West Virginia. Washington, D.C., January 1, 1950.]