Jongejan Jacobsz Posch was born circa 1712 in Hoogkarspel, North Holland, Netherlands to Jacob Posch (1675-1731) and Barber Abrahams (1675-1713) and died 4 February 1795 Hoogkarspel, North Holland, Netherlands of unspecified causes. He married Antje Ham (1714-1746) 19 February 1736 in Lutjebroek, North Holland, Netherlands. He married Grietje Verweij (c1742-1811) 10 April 1774 in Hoogkarspel, North Holland, Netherlands.
Children
| Name | Birth | Death | Joined with |
| Barber Posch (1737-1791) | 17 January 1737 Hoogkarspel, North Holland, Netherlands | 2 May 1791 Lutjebroek, North Holland, Netherlands | Arien Koomen (1739-1812) |
| Klaas Jongejansz (1738-1738) | |||
| Klaas Jongejansz (1739-1739) | |||
| Aaltje Posch (1741-) | |||
| Jacob Posch (1746-1833) | 17 July 1746 Hoogkarspel, North Holland, Netherlands | 10 February 1833 Hoogkarspel, North Holland, Netherlands | Neeltje Palenstijn (1740-1811) |
| Name | Birth | Death | Joined with |
| Pieter Posch (1774-bef1807) | |||
| Claas Jongejansz (1775-) | |||
| Jacob Jongejansz (1776-) | |||
| Geertje Jongejans (1778-) | |||
| Crelis Jongejansz (1782-) | |||
| Geertje Posch (1782-1810) | |||
Siblings