Campus of the University of Illinois at Urbana

The Main Quadrangle at the University of Illinois at Urbana–Champaign comprises the main campus of the university. It is a major quadrangle surrounded by buildings of the College of Liberal Arts and Sciences (LAS) and is the center of campus activities.

Several architects had been instrumental in the building of the campus. These include Ernest L Stouffer, Nathan Clifford Ricker, Charles A. Platt, James White, Clarence Howard Blackall, Holabird and Roche, and W.C. Zimmerman. Various campus buildings have been placed on the National Register of Historic Places; these include the Mumford House, Freer Hall, Evans Hall, Busey Hall, Main Library, Altgeld Hall, Round Barns, Kenney Gymnasium, Natural History Building, and Harker Hall. In addition, the Morrow Plots and the University of Illinois Observatory are designated as the National Historic Landmark. In celebration of the 2018 Illinois Bicentennial, the Main Quadrangle at the University of Illinois at Urbana–Champaign was selected as one of the Illinois 200 Great Places by the American Institute of Architects Illinois component (AIA Illinois).

Established as one of 37 public land-grant institutions established after the Morrill Land-Grant Colleges Act. The act was signed by Abraham Lincoln on July 2, 1862. The Morrill Act of 1862 granted each state in the United States a portion of land on which to establish a major public state university, one which could teach agriculture, mechanic arts, and military training, "without excluding other scientific and classical studies." This phrase would engender controversy over the Universitys initial academic philosophies, polarizing the relationship between the people of Illinois and the Universitys first president, John Milton Gregory. Illinois was one of seven commonwealths that had not formed a state university. The grant established eligibility for 480,000 acres of public scrip land valued at $600,000.

In the 1920s the University became known as one of the strongest fraternity campuses in the country. Fraternity row was established in the early 1900s while sorority housing concentrated on John Street. The fraternity district moved southward towards Chalmers Street and most sororities moved to Urbana by the Greek house building boom in the 1920s. In June 1929, the Alma Mater statue was unveiled. Like many Universities, the economic depression slowed construction and expansion which was during President Arthur C. Willards term. Willard served from 1934 to 1946. Even though expansion was slow but added Gregory Hall and the Illini Union. In the years following World War II, under president David Henry the university experienced rapid growth. The enrollment doubled and the academic standing improved which also resulted in the expansion of the campus and buildings. This included the creation of Willard Airport.

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:

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 Unions 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.

Harker Hall is immediately east of the Union and west of the Natural History Building. The building previously housed the Department of Chemistry and School of Law. The building was named after Judge Oliver Harker, who served as the Dean of the College of Law from 1903 to 1916. Harker Hall underwent extensive restoration in 1992 and is home to the University of Illinois Foundation, a non-profit organization that is responsible for the fund raising effort for the University of Illinois system.

The Natural History Building marks the northeast corner of the LAS buildings and has been largely evacuated as a result of structural issues discovered in 2010. The building was designed by Nathan Clifford Ricker and was placed on the National Register of Historic Places, and has several additions that expanded the building to the south in the early 20th century. The building used to house the universitys natural history museum with exhibits on geology and paleontology. The majority of these exhibits have been relocated to storage facilities or became part of the Spurlock Museum. The building was set to undergo a $70 million renovation beginning in 2014, and upon completion in 2016, will house the School of Earth, Society and Environment (which includes the departments of Atmospheric Sciences, Geology, and Geography and Geographic Information Science) and teaching labs of the School of Integrative Biology.

Noyes Laboratory is home to the chemistry department and lies directly south of the Natural History Building. The building is in the Richardsonian Romanesque style. Built in 1902, the Noyes Laboratory was the largest chemistry building in the nation upon its completion. The building was designated a National Historic Chemical Landmark by the American Chemical Society in 2002.

The Chemistry Annex provides additional facilities for the chemistry department; among them labs, classrooms, study halls and the Chemistry Learning Center, where students can receive additional assistance from TAs and professors. While Chemistry Annex is physically attached to the north side of Davenport Hall it is connected to Noyes Lab via an underground tunnel.

Completed in 1899, the Davenport Hall is one of the oldest academic buildings on campus. Davenport Hall is immediately south of Noyes Lab and the Chemistry Annex. It is still labeled with its original name, "College of Agriculture," but today is home to the departments of geography and anthropology. The building was named after Eugene Davenport, the former dean of the College of Agriculture.

The Foreign Language Building is south of Davenport Hall and houses all of the foreign language departments.

A popular myth is that the buildings distinctive architecture was a result of its being designed to house a supercomputer on campus called Plato. The building was supposedly designed so that if it was bombed, the buildings shell would fall outwards, protecting the supercomputer on the inside. It is also rumored that the buildings interior layout was a result of trying to confuse Soviet spies and prevent them from stealing secrets from the supercomputer. In reality, the buildings architecture is not actually all that unique and was a popular style of the day. In fact, just a few blocks to the west, one may find the Speech and Hearing Sciences Building, which is a 2-story clone of the building. Plato itself was real, but referred not to a secret government program, but rather to the first "modern" electronic learning system, the predecessor of course software like WebCT and Mallard. The mainframe computer that ran the Plato system was located in north campus, in a building which used to reside on the west side of the Bardeen Quad.

Foellinger Aditorium marks the southern terminus of the Main Quad, directly facing the Illini Union. Originally known as the "University Auditorium," the structure was renovated as part of a donation from Helene Foellinger of Fort Wayne, Indiana. The structure was designed by Charles Blackall, a prominent Boston-based architect who specialized in theater design.It is used for stage productions, speaker presentations, and large lecture classes.

Gregory Hall lies due west of Foellinger and houses numerous departments within the College of Media and LAS, including philosophy, economics, and history. The building is named in honor of John Milton Gregory, the former University President.

Lincoln Hall is northwest of Foellinger and is home to the College of Liberal Arts and Science, the largest college on campus. The building centers around a large auditorium. A big bust of Abraham Lincoln outside the entrance to the theater has its nose polished and nearly worn away after decades of students rubbing it for good luck prior to a test. Prior to the opening of the Spurlock Museum across the campus, Lincoln was the home of the World Heritage Museum.In Spring 2007, Illinois Governor Rod Blagojevichs proposed capital budget for the Fiscal Year 2008 called for $55.1 million for the $66.4 million renovation project. The building reopened for classes in Spring 2012.

The free standing pillar between Lincoln Hall and the English Building on the Main Quad is the Eternal Flame. Formerly an ever-burning oil lamp, it is now topped with an electric light. It is a memorial from the class of 1912.

Built in 1905, the English Building was designed by McKim, Mead and White, a firm known for Beaux-Arts architecture. It was originally known as the "Womans Building." At that time, according to Senator Henry Dunlap, it was supposed to "provide for every aspect of a womens education." This included hosting Household Science with its practice apartment, practice kitchens and dietetics classroom, the Child Development Study Program, and a womens dormitory with a gymnasium and a pool. The plan of the earliest building only included the westernmost portion of the building, as well as parts of the southern and northern legs.

Influenced by a new campus plan, an addition, designed by William Carbys Zimmerman, was added in 1913 to the Quad side of the Womens Building. This new addition of classrooms and meeting rooms formed the square shaped plan and called for the creation the East side, two-story, white portico. Another addition was completed in 1923 by James M. White.

In 1947, the Womans Building was renamed Bevier Hall in honor of Isabel Bevier, the founder of the Home Economics Department in 1900. This name lasted until the new Bevier Hall on Goodwin Avenue was dedicated in 1956. At that time it was renamed the English Building as the English Department took over. Among students on campus, the legend has it that a student drowned in a swimming pool and continues to haunt the building today. Today, the English Building is home to the English department and lies north of Lincoln Hall.