Benjamin was born say 1720. He was the son of Major Ralph Hart and Sarah Furman of Trenton Twp., old Hunterdon Co., NJ (in the area now Ewing Twp., Mercer Co.), and is presumed to have been born in that place. He married Hannah Cook in the 1740s.

In 1749, he and his brother Samuel were bequeathed half of their father's plantation. This tract was partly in Trenton Twp. and partly in Maidenhead Twp. (i.e., probably straddling the present-day Ewing-Lawrence border). The brothers later mortgaged this land together.

Benjamin was as a constable in Trenton Twp. in 1759. He made his own will on 6 May 1801, which was proved 13 November 1806. He is presumed to have died at his residence in present-day Ewing.

The Cooleys, in Genealogy of Early Settlers in Trenton and Ewing ... (1883), p. 100, report that Benjamin and Hannah Cook Hart had 17 children, as follows (most of the vital dates below come from other sources):

1. Martha, reportedly married "a Hart or Salathiel Pierson" (perhaps the former, as the latter is incorrect);
2. Jemima, single in 1801 though reported by the Cooleys as having married a "Jehiel Pierson" (this seems unlikely and is probably a confusion with her niece Jemima, who married Joseph Pierson, son of Salathiel);
3. William, born say 1745, married Hannah Laning, died 1818--linked below;
4. Sarah, died after 1816 (then unmarried);
5. Nathaniel, born after 1747 based on militia records, died after 1801;
6. Mary, possibly born 1751--see Mary Larison linked below;
7. Pamela, born about 1752, married Nathaniel Harcourt, died 1827--linked below;
8. Benjamin Jr., born say 1754, died 1813--linked below;
9. Absalom, a Revolutionary War soldier, married Susannah after 1779, died 1826--linked below;
10. Ralph, born abt. 1757, died 1830--linked below;
11. Stephen, born 30 Apr. 1758, a Revolutionary War soldier, apparently never married, died 1838--linked below;
12. Abigail, born abt. 1759, died unmarried in 1846--linked below;
13. John--no further record;
14. Hannah, died after 1816 (then unmarried);
15. Mercy, died unmarried after 1838;
16. Elijah, born 1 Jan. 1765, married Elizabeth Laning, died 1846--linked below;
17. Elisha--no further record (perhaps confused with Elijah).

Of these 17 children, Benjamin Hart mentioned 11 in his 1801 will. Two others (Pamela and Ralph) are documented through gravestones that can be identified with the persons referenced by the Cooleys. The daughter Mary may be the Mary Larison linked below, though documentation of this is needed. No documentation has been found to date relative to John, Mercy, and Elisha. Benjamin Hart provided for his many unmarried daughters in his will, but no married daughters are given bequests (probably because they had already received inheritance at the time of or after their marriages).

Note: Benjamin and his siblings were double cousins of John Hart, Signer of the Declaration of Independence. Their father's brother Edward Hart was John's father, and their mother's sister Martha Furman was John's mother. Many descendants of Benjamin and his father Ralph Hart are reported (falsely) as lineal descendants of the Signer, John Hart. They do, however, share John Hart's complete ancestry.