The University of Missouri (Mizzou, MU, University of Missouri–Columbia or simply Missouri) is a public research university located in the state of Missouri. In 1839 the university was founded in Columbia, Missouri, as the first public institution of higher education west of the Mississippi River. The largest university in Missouri, MU enrolls over 32,000 students in 20 academic colleges. The university is the flagship of the University of Missouri System which maintains campuses in Rolla, Kansas City and St. Louis. It became a four-campus system in 1963. MU is one of 34 public universities to be members of the Association of American Universities and the only one in Missouri. There are more than 248,000 MU alumni living worldwide, with almost half continuing to reside in Missouri. The University of Missouri was ranked 94th in the 2011 U.S. News & World Report rankings among the national universities, the highest-ranked public school in the state. The campus of the University of Missouri is 1,372 acres (5.55 km) just south of Downtown Columbia and is maintained as a botanical garden. The historical campus is centered on David R.