Los Angeles (pronounced /lɒs ˈændʒələs/ los-AN-jə-ləs; Spanish: [los ˈaŋxeles], Spanish for "The Angels") is the second largest city in the United States, the largest city in the state of California and the Western United States, with a population of 3.83 million within its administrative limits on a land area of 498.3 square miles (1,290.6 km). The urban area of Los Angeles extends beyond the administrative city limits with a population of over 14.8 million, it is the 14th largest urban area in the world, affording it megacity status. The Los Angeles–Long Beach–Santa Ana metropolitan statistical area (MSA) is home to nearly 12.9 million residents while the broader Los Angeles-Long Beach-Riverside combined statistical area (CSA) contains nearly 17.8 million people. Los Angeles is also the seat of Los Angeles County, the most populated and one of the most multicultural counties in the United States. The city's inhabitants are referred to as "Angelenos" (/ændʒɨˈliːnoʊz/).

Los Angeles was founded on September 4, 1781, by Spanish governor Felipe de Neve as El Pueblo de Nuestra Señora la Reina de los Ángeles del Río de Porciúncula (The Village of Our Lady, the Queen of the Angels of the river of Porziuncola). It became a part of Mexico in 1821, following its independence from Spain. In 1848, at the end of the Mexican-American War, Los Angeles and the rest of California were purchased as part of the Treaty of Guadalupe Hidalgo, thereby becoming part of the United States. Los Angeles was incorporated as a municipality on April 4, 1850, five months before California achieved statehood.

Often known by its initials, L.A., and nicknamed the City of Angels, Los Angeles is a world center of business, international trade, entertainment, culture, media, fashion, science, technology, and education. It 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. In 2008, Los Angeles was named the world's eighth most economically powerful city by Forbes.com, third in the U.S. behind New York City and Chicago. The Los Angeles combined statistical area (CSA) has a gross metropolitan product (GMP) of $831 billion (as of 2008), making it the third largest economic center in the world, after the Greater Tokyo Area and the New York metropolitan area. As the home base of Hollywood, it is known as the "Entertainment Capital of the World", leading the world in the creation of motion pictures, television production, video games, and recorded music. The importance of the entertainment business to the city has led many celebrities to call Los Angeles and its surrounding suburbs home. Los Angeles hosted the 1932 and 1984 Summer Olympics.

Los Angeles enjoys a subtropical climate, with an average of 35 days with measurable precipitation annually.