Los Angeles County High School for the Arts (Arts High or LACHSA,  /ˈlɔːksə/) is a Visual and Performing Arts high school located on the campus of California State University, Los Angeles in Los Angeles, California, United States. Founded in 1984, the public, tuition-free school offers both college preparatory courses and conservatory style training. Though it shares facilities with the university, the two schools' activities are usually separate. It is operated by the Los Angeles County Office of Education. LACHSA maintains a unique affiliation with International Polytechnic High School, which is also run by LACOE.

The school specializes in the training of music, theater, dance, visual arts, and film. It is one of two arts high schools in Los Angeles that allows students from any district within Los Angeles County to attend, the other being Charter High School of the Arts in Van Nuys.

Acceptance into the school is based on an audition process for the approximately 130 spots available for incoming students, about 90% of whom are freshman. In 2011 more than 1000 students auditioned, the highest number ever.

Los Angeles County (incorporated as the County of Los Angeles) is a county in the U.S. state of California. As of the 2010 census, the county had a population of 9,818,605, making it the most populous county in the United States. Los Angeles County alone is more populous than 42 individual U.S. states. The county seat is the city of Los Angeles, the largest city in California and the second-largest city in the United States (after New York City).

Los Angeles County also includes two offshore islands, San Clemente Island and Santa Catalina Island. The county is home to 88 incorporated cities and many unincorporated areas. At 4,083 square miles (10,570 km²), it is larger than the combined areas of the states of Rhode Island and Delaware.

The county is home to over a quarter of all California residents and is one of the most diverse counties in the country.

Los Angeles County was one of the original counties of California, created at the time of statehood in 1850. The county's large area included parts of what is now Kern County, San Bernardino County, Riverside County and Orange County. These parts of the county's territory were given to San Bernardino County in 1853, to Kern County in 1866 and to Orange County in 1889. In 1893, part of San Bernardino County became Riverside County.

Los Angeles (ⁱ/lɒs ˈændʒələs/ loss-AN-jə-ləs; Spanish: [los ˈaŋxeles], which is written Los Ángeles; British pronounciation /lɒs ˈændʒəliːz/ loss-AN-jə-leez) with a population at the 2010 United States Census of 3,792,621, is the most populous city in the state of California, and the second most populous in the United States, after New York City. It has an area of 468.67 square miles (1,213.8 km²), and is located in Southern California. Often known by its initials L.A., 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 12,828,837 and nearly 18 million people 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".