The Pennsylvania State University, commonly referred to as Penn State or PSU, is a public research university with campuses and facilities throughout the Commonwealth of Pennsylvania, United States. Founded in 1855, the university has a threefold mission of teaching, research, and public service. Its instructional mission includes undergraduate, graduate, professional and continuing education offered through resident instruction and online delivery. Its University Park campus, the flagship campus, lies within the Borough of State College and College Township. The Penn State Dickinson School of Law has facilities located in both Carlisle and University Park and the College of Medicine is located in Hershey. Penn State has another 19 commonwealth campuses and 5 special-mission campuses located across the state. Penn State University is ranked among the top-fifteen public universities nationally and is considered to be one of America's Public Ivy universities, which recognizes top public research universities in the United States. Annual enrollment at the University Park campus totals more than 44,000 graduate and undergraduate students, making it one of the largest universities in the United States. It has the world's largest dues-paying alumni association. The university's total enrollment in 2009–10 was approximately 94,300 across its 24 campuses and online through its World Campus. The university offers more than 160 majors among all its campuses and administers a US$1.52 billion (as of April 30, 2010) endowment. The university's research expenditures exceeded $753 million for the 2009 fiscal year and was ranked 9th among U.S. universities in research income by the National Science Foundation. Annually, the university hosts the Penn State IFC/Panhellenic Dance Marathon (THON), which is the world's largest student-run philanthropy. The university's athletics teams compete in Division I of the NCAA and are collectively known as the Penn State Nittany Lions. They compete in the Big Ten Conference for most sports.