She was the youngest and third daughter of Governor Robert Bowie and Priscilla Mackall. She married Dr. Reverdy Ghiselin on December 25, 1804 at the Executive Mansion in Annapolis, Maryland. He was an eminent physician in Annapolis and for several years had charge of the land office succeeding his father. Several times he was a member of the Governor's council and served twice under that capacity under Gov. Robert Bowie. He was highly educated and during the French Revolution he studied in Paris as a student. He acted as the Surgeon in the Army during the War of 1812.
He acquired Brookfield, which was the former residence to Thomas Contee, He moved his family there. He died at the residence and is buried not far from the house. Margaret died in 1850 while on a visit to Baltimore and is buried beside him.