James Carson Brevoort (New York City 10 July 1818 – Brooklyn, New York 7 December 1887) was a United States collector of rare books and coins. He served as superintendent of the Astor Library for two years, also serving as trustee.
He received his early education at home, in France, and at Hofwyl, near Berne, Switzerland. He then studied at the École Centrale des Arts et Manufactures in Paris, and was graduated with the diploma of a civil engineer.
On returning to the United States, he accompanied his uncle, James Renwick, one of the commissioners on the northeastern boundary survey. In 1838 he went abroad as private secretary to Washington Irving, U. S. Minister to Spain. After serving a year in this capacity, he spent several years in European travel, and returned home in 1843. Two years later he married the daughter of Judge Leffert Lefferts, of Brooklyn, where he afterward resided, serving on the board of education, and as one of the constructing board of water commissioners.
He became a regent of the University of New York in 1861, and the same year received the degree of LL.D. from Williams College. For ten years, beginning in 1863, he was president of the Long Island Historical Society. In 1868, he was elected a member of the American Antiquarian Society. For two years, March 1876 to February 1878, he was superintendent of the Astor Library in New York City, of which he had been a trustee since 1852. He oversaw the beginning of a card catalog for the Astor collection. He resigned as a trustee in September 1878. He was a member of the New York Historical Society, the Academy of Natural Sciences, the American Geographical Society, the Massachusetts Historical Society, the Pennsylvania Historical Society, and numerous other scientific, literary, and artistic associations, in which he was always actively involved.