Mary Clarke Barrett was born 1740 in Massachusetts, United States to Richard Clark (1711-1795) and Elizabeth Winslow (1707-1765) and died 25 August 1761 Boston, Suffolk County, Massachusetts, United States of unspecified causes. She married Samuel Barrett (1738-1798) 1759 in Boston, Suffolk County, Massachusetts.
Children
| Name | Birth | Death | Joined with |
| Sarah Barrett (1763-1809) | 13 March 1763 Boston, Suffolk County, Massachusetts, United States | 17 February 1809 Boston, Suffolk County, Massachusetts, United States | Samuel Cabot (1759-1819) |
Siblings
| Name | Birth | Death | Joined with |
| Hannah Clarke (1724-1761) | |||
| William Clarke (1734-1761) | |||
| Elizabeth Clarke (1735-) | |||
| Edward Clark (1737-1770) | |||
| Mary Clarke (1740-1761) | 1740 Massachusetts, United States | 25 August 1761 Boston, Suffolk County, Massachusetts, United States | Samuel Barrett (1738-1798) |
| Joseph Lee Clark (1740-) | |||
| Jonathan Clark (1744-) | |||
| Susanna Farnham Clark (1745-1836) | |||
| Isaac Winslow Clark (1746-1822) | |||
| Sarah Clark (1750-) | |||
| Lucy Clark (1752-1847) | |||
| Richard Clark (1756-1767) | |||