Los Angeles lies in a basin in Southern California, adjacent to the Pacific Ocean, with mountains as high as 10,000 feet and deserts. The city is the seat of Los Angeles County, the most populous county in the United States. The Los Angeles metropolitan area is home to a population of 13.1 million, making it the second-largest metropolitan area in the nation after that of New York. Greater Los Angeles includes metro Los Angeles as well as the Inland Empire and Ventura County. It is the second most populous U.S. combined statistical area, also after New York, with a 2015 estimate of 18.7 million people. Wikipedia

Orange County is located in the Los Angeles, CA area. Although mostly suburban, it is the second most densely populated county in the state, behind San Francisco County. The county's three most populous cities are Anaheim, Santa Ana, and Irvine. Santa Ana is also the county seat. Six cities in Orange County are on the Pacific coast, including Seal Beach, Huntington Beach, Newport Beach, Laguna Beach, Dana Point, and San Clemente. Wikipedia 

Ventura County comprises the Oxnard-Thousand Oaks-Ventura, CA Metropolitan Statistical Area, which is also included in the Los Angeles-Long Beach, CA area. It is also considered the southernmost county along the California Central Coast. Two of the California Channel Islands are part of the county: Anacapa Island, which is the most visited island in Channel Islands National Park, and San Nicolas Island. Wikipedia