The main campus of the University of Illinois, commonly known as the UI-UC campus, is located at the twin cities of Urbana-Champaign, about 135 miles south of Chicago, Illinois, U.S.A. The campuses of Chicago Circle and the Medical Center, both located in Chicago, are other components of the University of Illinois system. Many departments and colleges of the UI-UC campus, especially in the fields of science and technology, have outstanding reputations for research achievement. The University Library ranks first in size among state universities and third among all universities in the United States. Its total collection reaches approximately 5.5 million volumes.