Irvine is a master-planned city in Orange County, California, United States. 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 212,375 as of the 2010 census; in 2016 the city's population was 258,386. A number of corporations, particularly in the technology and semiconductor sectors, have their national or international headquarters in Irvine. Irvine is also home to several higher education institutions including the University of California. The Gabrieleño indigenous group inhabited Irvine about 2,000 years ago. Gaspar de Portolà, a Spanish explorer, came to the area in 1769, which led to the establishment of forts, missions and cattle herds. The King of Spain parceled out land for missions and private use. Irvine borders Tustin to the north, Santa Ana to the northwest, Lake Forest to the east, Laguna Hills and Laguna Woods to the southeast, Costa Mesa to the west, and Newport Beach to the southwest. Late spring and early summer in Irvine is subject to the June Gloom phenomenon widespread in southern California, with overcast mornings and occasional drizzle. Late summer and autumn are warm and mostly dry, with occasional bouts of humid weather extending from Pacific hurricanes off the west coast of Mexico. Winters are mild, with most winters having no frost, and can be hot and dry when the Santa Ana winds blow.