There have always been only eight Ivy League schools since its founding as an organization in 1945, and it is highly improbable for additional schools to ever be added, according to College Confidential. The term officially refers to an athletic conference agreement between eight of America's oldest colleges.
The eight Ivy League schools are Harvard, Yale, Princeton, Dartmouth, Brown, Columbia, Penn and Cornell, as listed on The Ivy League website. In 1945, an agreement was signed binding the schools together as a football conference, and the agreement was expanded to all intercollegiate sports in 1954. Although the Ivy League agreement was originally geared toward athletics, the Ivy League designation has expanded to signify academic excellence, College Confidential explains. The Ivy League name is trademarked and may only refer to the official eight schools.