Jared Mansfield (1759–1830), mathematician, surveyor, and educator, was born in New Haven, Connecticut. He attended Yale College (later Yale University) in the class of 1777 but was expelled during his senior year for misconduct. In 1786 Mansfield became rector of New Haven’s Hopkins Grammar School, and Yale eventually awarded him a master’s degree in 1787. He resigned from Hopkins in 1790 but returned a few months later and continued as its head until 1795. Mansfield afterwards taught briefly in Philadelphia before returning to lead a private school in New Haven. In 1801 he published Essays, Mathematical and Physical: containing New Theories and Illustrations of some very Important and Difficult Subjects of the Sciences. Never Before Published (New Haven, [1801]; Sowerby, description begins E. Millicent Sowerby, comp., Catalogue of the Library of Thomas Jefferson, 1952–59, 5 vols. description ends no. 3733). This ambitious work brought Mansfield to the attention of TJ, who in 1802 appointed him captain of the United States Army Corps of Engineers and professor of mathematics at the United States Military Academy. Mansfield left West Point the following year when TJ appointed him surveyor general of the United States, a position he held until 1812 and during which time he lived in Marietta and Cincinnati while he surveyed Ohio and the Northwest Territory. He was promoted to major in 1805 and lieutenant colonel in 1808 before resigning his army commission in 1810. President James Madison appointed Mansfield professor of experimental and natural philosophy at West Point in 1812, and after being diverted to supervise the construction of fortifications during the War of 1812, he taught there from 1814 until resigning in 1828. Mansfield moved thereafter to Cincinnati. He died during a visit to New Haven (DAB description begins Allen Johnson and Dumas Malone, eds., Dictionary of American Biography, 1928–36, 20 vols. description ends ; Dexter, Yale Biographies, 3:644, 691–4; PTJ description begins Julian P. Boyd, Charles T. Cullen, John Catanzariti, Barbara B. Oberg, James P. McClure, and others, eds., The Papers of Thomas Jefferson, 1950– , 43 vols. description ends , 37:131–2, 348–9, 40:410–2; JEP description begins Journal of the Executive Proceedings of the Senate of the United States description ends , 1:422, 424, 453, 455, 2:22, 69, 301 [27 Apr., 3 May 1802, 11, 15 Nov. 1803, 24 Feb. 1806, 19 Feb. 1808, 9 Nov. 1812]; Heitman, U.S. Army description begins Francis B. Heitman, comp., Historical Register and Dictionary of the United States Army, 1903, repr. 1994, 2 vols. description ends , 1:688; The Centennial of the United States Military Academy at West Point, New York. 1802–1902 [1904], 2:53–4, 63; Hartford Connecticut Courant, 9 Feb. 1830; New-York Morning Herald, 13 Feb. 1830).