The University of Illinois at UrbanaChampaign (U of I, University of Illinois, UIUC, or simply Illinois) is a public research-intensive university in the U.S. state of Illinois. It is the flagship campus of the University of Illinois system. The University of Illinois at UrbanaChampaign is the second oldest public university in the state (after Illinois State University), and is a founding member of the Big Ten Conference. It is considered a Public Ivy and is a member of the Association of American Universities. The university is designated as a RU/VH Research University (very high research activities). The campus library system possesses the second-largest university library in the United States and the fifth-largest in the country overall. The university comprises 17 colleges that offer more than 150 programs of study. Additionally, the university operates an extension that serves 2.7 million registrants per year around the state of Illinois and beyond.