Southern California

Southern California is a megapolitan region occupying the southern portion of the US state of California. The region is bordered to the east by the states of Nevada and Arizona, to the south by the international border of the United States and Mexico, and to the west by the Pacific Ocean. There is no official definition for the northern boundary of Southern California, but most include all the land south of the Sierra Nevada Mountains and the Tehachapi Mountains. Southern California also includes several offshore islands such as the Channel Islands, deserts such as the Mojave and Colorado, and the largest lake in California, the very salty Salton Sea. The largest metropolitan area is Los Angeles, the nation's second largest metro area. Other metro areas include San Diego, Riverside-San Bernardino-Ontario, and the lightly populated El Centro. 

Southern California is a culturally diverse and well known area worldwide. Many tourists travel here for its fine year-round weather along the coast, open dramatic spaces, beaches, and numerous amusement parks. Southern California is a major economic center for the state of California and the United States.

Southern California, often abbreviated as SoCal, is a megaregion or megapolitan area in the southern portion of the US state of California. Large urban areas include the Greater Los Angeles, and Greater San Diego. The region stretches along the coast from about Santa Barbara to the United States and Mexico border, and from the Pacific Ocean inland to the Nevada and Arizona borders. The heavily built-up urban area stretches along the coast from Ventura, through the Greater Los Angeles Area, the Inland Empire and down to San Diego. Southern California is a major economic center for the state of California and the United States.

San Diego

San Diego is a major city in California, on the coast of the Pacific Ocean in Southern California, approximately 120 miles (190 km) south of Los Angeles and immediately adjacent to the border with Mexico. San Diego is the eighth-largest city in the United States and second-largest in California and is one of the fastest growing cities in the nation. San Diego is the birthplace of California and is known for its mild year-round climate, natural deep-water harbor, extensive beaches, long association with the U.S. Navy, and recent emergence as a healthcare and biotechnology development center. The population was estimated to be 1,322,553 as of 2012.

The city is the seat of San Diego County and is the economic center of the region as well as the San Diego–Tijuana metropolitan area. San Diego's main economic engines are military and defense-related activities, tourism, international trade, and manufacturing. The presence of the University of California, San Diego (UCSD), with the affiliated UCSD Medical Center, has helped make the area a center of research in biotechnology.

Los Angeles

Officially the City of Los Angeles, often known by its initials L.A., is the most populous city in the U.S. state of California and the second-most populous in the United States, after New York City, with a population at the 2010 United States Census of 3,792,621. It has a land area of 469 square miles (1,215 km2), and is located in Southern California.

Nicknamed the City of Angels, Los Angeles is a global city, with strengths in business, international trade, entertainment, culture, media, fashion, science, sports, technology, education, medicine and research and has been ranked sixth in the Global Cities Index and 9th Global Economic Power Index. The city is home to renowned institutions covering a broad range of professional and cultural fields and is one of the most substantial economic engines within the United States. The Los Angeles combined statistical area (CSA) has a gross metropolitan product (GMP) of $831 billion (as of 2008), making it the third-largest in the world, after the Greater Tokyo and New York metropolitan areas. Los Angeles includes Hollywood and leads the world in the creation of television productions, video games, and recorded music; it is also one of the leaders in motion picture production. Additionally, Los Angeles hosted the Summer Olympic Games in 1932 and 1984.

The city is the focal point of the larger Los Angeles–Long Beach–Santa Ana metropolitan statistical area and Greater Los Angeles Area region, which contain 13 million and over 18 million people in combined statistical area respectively as of 2010, making it one of the most populous metropolitan areas in the world and the second-largest in the United States. Los Angeles is also the seat of Los Angeles County, the most populated and one of the most ethnically diverse counties in the United States, while the entire Los Angeles area itself has been recognized as the most diverse of the nation's largest cities. The city's inhabitants are referred to as Angelenos.

Orange County

Orange County is a county in the U.S. state of California. Its county seat is Santa Ana. As of the 2010 census, its population was 3,010,232, making it the third most populous county in California, behind Los Angeles County and San Diego County. It is also the second most populous county in the Greater Los Angeles Area, after Los Angeles County. It is the sixth most populous county in the United States as of 2009 and the smallest county in Southern California by area. It is roughly half the size of Ventura County, Southern California's next smallest county.

It is the second most densely populated county in the state, second only to San Francisco County. The county is famous for its tourism as the home of attractions like Disneyland, Knott's Berry Farm, and several beaches along its more than 40 miles (64 km) of coastline. It is known for its political conservatism — a 2005 academic study listed three Orange County cities as among America's 25 most conservative, making it one of two counties in the nation containing more than one such city. (Maricopa County, Arizona also has three cities on the list. It is part of the Tech Coast.