Irvine (/ˈɜːrvaɪn/) is a master-planned city in southern Orange County, California, United States, in the Los Angeles metropolitan area. The Irvine Company started developing the area in the 1960s and the city was formally incorporated on December 28, 1971. The 66-square-mile (170 km2) city had a population of 307,670 at the 2020 census, it is the 63rd most populous city in the United States.