Jacobus "James" Roosevelt III (January 10, 1760 – February 6, 1847) was an American businessman and politician from New York City.

At one point, he owned stony farmland at Harlem, now occupied by 120 city blocks between 110th and 125th streets and Fifth Avenue and the East River.

In 1819, Roosevelt removed to Poughkeepsie and bought a large tract of land on the Hudson River called Mount Hope.

His first marriage took place on November 15, 1786 in New York City to Maria Eliza Walton (1769–1810),[4] the daughter of Admiral Gerard Walton (died 1821) and a descendant of Wilhelmus Beekman, who was the treasurer of the Dutch West India Company, mayor of New York City,[5][6] governor of Delaware from 1653 to 1664, and governor of Pennsylvania from 1658 to 1663.

[7][8] Their children who survived infancy were:[9] After Walton's death in 1810, he married on September 2, 1812, for the second time to Catharine Elizabeth Barclay (c. 1783–1816) in New York City.