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.