Mary Bemis Hagar was born 10 December 1624 in Dedham, Essex, England to Joseph Bemis (1582-1628) and Anne Spray (1593-1628) and died 16 December 1695 Watertown, Middlesex County, Massachusetts of unspecified causes. She married William Hagar (1620-1684) 20 March 1644 in Watertown, Middlesex County, Massachusetts.
Children
| Name | Birth | Death | Joined with |
| Mary Hagar (1645-1646) | |||
| Samuel Hagar (1647-1703) | 20 November 1647 Watertown, Middlesex County, Massachusetts | 16 February 1703 Watertown, Middlesex County, Massachusetts | Sarah Mixer (1657-1745) |
| Hannah Hagar (1649-1702) | 21 November 1649 Watertown, Middlesex County, Massachusetts | 6 May 1702 Watertown, Middlesex County, Massachusetts | Joseph Priest (1649-1697) |
| Ruhamah Hagar (1647-1702) | |||
| Sarah Hagar (1651-1746) | 1 September 1651 Watertown, Middlesex County, Massachusetts | 7 March 1746 Weston, Middlesex County, Massachusetts | Nathaniel Whitney (1646-1732) |
| Susanna Hagar (1653-1722) | |||
| Diana Hagar (1655-) | |||
| Elizabeh Hagar (1658-) | |||
| William Hagar (1659-) | 20 November 1647 Waltham, Middlesex County, Massachusetts | Sarah Benjamin (1663-1745) | |
| Rebeckah Hagar (1661-1735) | |||
| Abigail Hagar ((1664-1736) | |||
| Mehitable Hagar (1665-1691) | |||
Siblings
| Name | Birth | Death | Joined with |
| Issac Bemis (1615-) | |||
| Luke Bemis (1615-) | |||
| Joseph Bemis (1619-1684) | 1619 Dedham, Essex, England | 7 August 1684 Watertown, Middlesex County, Massachusetts | Sarah Finch (1620-1712) |
| Abraham Bemis (1621-) | |||
| Mary Bemis (1624-1695) | 10 December 1624 Dedham, Essex, England | 16 December 1695 Watertown, Middlesex County, Massachusetts | William Hagar (1620-1684) |
| James Bemis (1626-1665) | |||
| Susanna Bemis (1628-) | |||