State College is the largest borough in Centre County in the U.S. state of Pennsylvania. It is the principal city of the State College, Pennsylvania Metropolitan Statistical Area which encompasses all of Centre county. As of the 2000 census, the borough population was 38,420, (estimated 38,720 in 2007) and roughly double that total lived in the borough plus the surrounding townships. Of that population, 20,011 or 52.1% are males and 18,409 or 47.9% are females. The town is dominated economically and demographically by the presence of the main campus of the Pennsylvania State University, colloquially referred to as Penn State. "Happy Valley" is an often-used term to refer to the State College area, including the borough and the townships of College, Harris, Patton, and Ferguson. In 2008, State College was ranked as the second safest metropolitan area in the United States by the CQ Press, and ranked safest in 2009. The area is served by University Park Airport.