was born on 1 September 1735. He was the son of David Demarest
and Greetje Abramse Haring
. Jacobus Demarest was baptized on 7 September 1735 at Dutch Reformed Church, Tappan, Rockland County, New York. He married Sarah Peeke
, daughter of Johannes Peeke
and Susanna Demarest
, on 28 April 1764 at Dutch Reformed Church, North Schraalenburgh, Bergen County, New Jersey. Jacobus Demarest Bergen County militia in the Revolutionary War circa 1778 at Bergen County, New Jersey. He died on 27 November 1805 at age 70. He was buried after 27 November 1805 at Dutch Reformed Churchyard, North Schraalenburgh, Bergen County, New Jersey.