Mary Sampson Thayer was born circa 1694 in Duxbury, Plymouth County, Massachusetts to Stephen Sampson (1638-1714) and Elizabeth Sprague (1657-1727) . She married Samuel Thayer (1696-1764) 13 August 1716 in Mendon, Worcester County, Massachusetts.
Children
| Name | Birth | Death | Joined with |
| Abigail Thayer (1718-1774) | |||
| Samuel Thayer (1721-) | |||
| Zilpah Thayer (1722-) | 13 September 1722 | 17 October 1761 | John Holbrook (1717-1773) |
| Mary Thayer (1723-) | |||
| Thankful Thayer (1725-1798) | 4 August 1725 Mendon, Worcester County, Massachusetts | 10 December 1798 Massachusetts | Sylvanus Holbrook (1715-1782) |
| Comfort Thayer (1728-1761) | |||
| Margaret Thayer (1730-) | |||
| Susanna Thayer (1731-) | |||
| Stephen Thayer (1733-1781) | |||
Siblings
| Name | Birth | Death | Joined with |
| Benjamin Sampson (1686-1758) | |||
| John Sampson (1688-1770) | 17 August 1688 Duxbury, Plymouth County, Massachusetts | 26 January 1770 Duxbury, Plymouth County, Massachusetts | Priscilla Bartlett (1696-1758) |
| Hannah Sampson (1690-1753) | |||
| Mary Sampson (1694-) | 1694 Duxbury, Plymouth County, Massachusetts | Massachusetts | Samuel Thayer (1696-1764) |
| Elizabeth Sampson (1696-1762) | |||
| Dorcas Sampson (1698-1754) | |||