Jacob Rutsen Hardenbergh (22 February 1735/6[a] – 30 October 1790) was an American Dutch Reformed clergyman, colonial and state legislator, and educator.

Hardenbergh was descended from a Dutch family that settled New Amsterdam in the seventeenth century and was prominent in New York colonial affairs.

He prepared for ministry at the home of the Reverend John Frelinghuysen, a prominent Dutch Reformed minister near Somerville, New Jersey.

After being ordained, Hardenbergh was called to serve congregations in New Jersey's Raritan River valley, and later in Ulster County, New York.

During the American Revolution, Hardenbergh served as a delegate for New Jersey's Provincial Congress which ratified the Declaration of Independence and to frame the state's first constitution (1776).

Jacob Rutsen Hardenbergh was born on 22 February 1735/36 at Rosendale near Kingston, Ulster County, New York in the Hudson River Valley.

[4] Born in Amsterdam, Dinah was the daughter of Louis Van Bergh, a wealthy merchant who was "engaged in East India trade.

The First Great Awakening was an evangelical revival in the 1730s and 1740s that revitalized Christian beliefs in Protestant Europe and the North American colonies through powerful preaching that gave listeners a sense of deep personal revelation of their need of salvation by Jesus Christ.

With John Frelinghuysen's unexpected death in 1754, Hardenbergh, as his last theological student, assumed the pulpits of five congregations in central New Jersey served by his teacher.

[10]: p.74 During the Revolution, General Washington, a personal friend of the Hardenbergh family, established a headquarters at Raritan in the home of John Wallace and frequently attended services sitting "at the head of the elder's pew".

[10]: p.75  In 1779, the church at Raritan was burned by British forces under Colonel John Graves Simcoe who had intensified efforts to capture Washington.

[10]: pp.74–75 In 1781, Hardenbergh resigned his pastorates in New Jersey to accept the call to congregations at Marbletown, Rochester, and Wawarsing in Ulster County, New York.

[5][16] The inscription on his grave was written by the Reverend John Henry Livingston and exhorts mourners to "go walk in his virtuous footsteps; and when you have finished the work assigned you, you shall rest with him in eternal peace.

"[10]: p.78  It eulogises Hardenbergh as "a zealous preacher of the Gospel, and his life and conversation afforded, from his earliest days, to all who knew him, a bright example of real piety...a steady patriot, and in his public and private conduct he manifested himself to be the enemy of tyranny and oppression, the lover of freedom, and the friend of his country.

"[10]: p.78  At the time of his death, Hardenbergh was a wealthy man—largely due to monies and property inherited from his father and grandfather—and was the owner of 40,000 acres of land in Ulster County that was once part of his grandfather's patent.

Cornelius's son, Augustus Albert Hardenbergh, served two separate terms as a United States Congressman from New Jersey, 1875 to 1879 and 1881 to 1883.