Corona is a city in Riverside County, California, United States. As of the 2010 census, the city had a population of 152,374, up from 124,966 at the 2000 census. The city of Norco and Riverside lie to the northeast, Chino Hills to the northwest, Yorba Linda, and the Cleveland National Forest to the southwest; unincorporated areas of Riverside County line all of its other borders.

Corona, founded at the height of the Southern California citrus boom in 1886, is advantageously situated at the upper end of the Santa Ana River Canyon, the only significant pass through the Santa Ana Mountains. The town of Corona once laid claim to the title "Lemon Capital of the World." A museum there presents the lemon's former role in the local economy. The city derived its name (and its nickname, The Circle City) from the curious layout of its streets, with a standard grid enclosed by the circular Grand Boulevard, one mile in diameter. The street layout was designed by Hiram Clay Kellogg, a civil engineer from Anaheim who was an influential figure in the early development of Orange County.^{[citation needed]}

California (pronounced ⁱ/kælɨˈfɔrnjə/) is a state located on the West Coast of the United States. It is by far the most populous U.S. state, and the third most extensive (after Alaska and Texas). It is home to the nation's second- and sixth-largest census statistical areas (Los Angeles Metropolitan Area and San Francisco Bay Area), and eight of the nation's fifty most populated cities (Los Angeles, San Diego, San Jose, San Francisco, Fresno, Sacramento, Long Beach and Oakland). The capital city is Sacramento.

California's diverse geography ranges from the Pacific Coast in the west, to the Sierra Nevada mountains in the east – from the Redwood–Douglas-fir forests of the northwest, to the Mojave Desert areas in the southeast. The center of the state is dominated by Central Valley, a major agricultural area. California contains both the highest and lowest points in the contiguous United States (Mount Whitney and Death Valley), and has the third-longest coastline of all states (after Alaska and Florida). Earthquakes are a common occurrence due to the state's location along the Pacific Ring of Fire: about 37,000 are recorded annually.