There are fifteen buildings on or very close to the Main Quad that comprise the main campus of the university. They are listed clockwise with the Illini Union on the north side as the top:

Illini Union Edit Main article: Illini Union

Illini Union The Illini Union is the student union at the northernmost point of the Main Quad and lies on Green Street. Its Georgian Revival style was conceived by Ernest L. Stouffer, University architect, and Howard Cheney, consulting architect. The cupola, clock, and bell from University Hall (demolished) are retained in the Union. Much of the original woodwork was carved by John C. Freiburg. The building was constructed in 1939–40; a $6.9 million addition in 1960 dramatically increased its size and usefulness. The Union replaced the University Hall, one of the first buildings on the campus. It is the center of student activities and hundreds of registered student organizations. Numerous expos, conferences, and events are held in the Union's ballrooms and facilities. There is a full-service underground food court and bowling alley as well as a university operated hotel in the upper floors.