Corvallis is a city in central western Oregon, United States. It is the county seat of Benton County and the principal city of the Corvallis, Oregon Metropolitan Statistical Area, which encompasses all of Benton County. As of the 2010 United States Census, the population was 54,462. Its population was estimated by the Portland Research Center to be 55,298 in 2013. Corvallis is the location of Oregon State University and a large Hewlett-Packard research campus.