James Hillhouse (October 20, 1754 - December 29, 1832), of New Haven, Connecticut, was a real estate developer responsible for much of the current look of New Haven, a politician, and a treasurer of Yale University.

He was born in Montville, Connecticut, the son of William Hillhouse, and adopted by his childless uncle and aunt, James Abraham and Mary Lucas Hillhouse. He graduated from Yale in 1773, and became a captain in the Revolutionary War. He was active in the drive to plant the elm trees that gave New Haven the nickname of the Elm City.

He was a member of the Connecticut State House of Representatives, 1780, United States Congressman from Connecticut at-large, 1791-96, and United States Senator from Connecticut, 1796-1810. He was interred at Grove Street Cemetery.