California is a state in the United States. It is located on the Pacific coast of North America In the western United States. With an area of 163,696 square miles (423,970 square kilometers), it is the third largest state in the United States after Alaska and Texas. It is also the most populous state in the United States, with a population of 38.33 million.
California officially became the 31st state on September 9, 1850. Before that time it was ruled by the Spanish Empire and was part of New Spain. Even before that native tribes had lived there for thousands of years. The land that would become part of California was given to the United States after they won the Mexican American War. During the Gold Rush of the 1850s, California grew as settlers came to seek their fortunes. The cities of San Francisco,Stockton, and Sacramento sprang up as a result. San Francisco is a major city on the western coast of the United States. California is prone to earthquakes because it lies on the San Andreas Fault, a fault between the Pacific and North American Plates. Some famous and devastating earthquakes include the 1906 earthquake and the 1989 Loma Prieta earthquake. In 1937 The Golden Gate Bridge was built, connecting San Francisco and Marin County. The bridge is one of California's most famous landmarks.
In Southern California the town of Los Angeles is the center of the U.S. entertainment industry, based in Hollywood. More recently California has been the home of Silicon Valley. Located south of San Francisco and north of San Jose, this area has been the site of major technological innovation. Including being the birthplace of Apple Computer, the site of many major technological innovations, and home to many startup software companies. Major universities in California include Stanford, the UCs, San Jose State, and Caltech.