Los Angeles was originally named on September 4, 1781. A group of 12 families from the San Gabriel Mission in the San Gabriel Valley, known as the Pobladores, - 46 men, women and children from the San Gabriel Mission led by Captain Rivera y Moncada - established a community in what is now known as the City of Los Angeles. They named it El Pueblo de Nuestra Senora la Reina de Los Angeles de Porciuncula after a nearby river (the River of Our Lady the Queen of the Angels of Porciuncula).

California was ruled by Spain until 1822, when Mexico assumed jurisdiction. After a two-year period of hostilities with Mexico beginning in 1846, the area came under U.S. control. In 1848 the Treaty of Guadalupe Hidalgo made California a United States territory. The County of Los Angeles was established on February 18, 1850 as one of the 27 original counties in California. 

The city of Los Angeles, the first city within Los Angeles County, was incorporated just two months later, on April 4, 1850. More than 30 years later, in 1886, Santa Monica and Pasadena were established. The county established Monrovia a year later, followed by Pomona, Long Beach, South Pasadena, and Compton in 1888. Redondo Beach became a city in 1892, as did Whittier and Azusa in 1898. 

By 1900, the population of Los Angeles jumped from 2300 in 1860 to 100,000, thanks in part to the prodding of magazine and newspaper editor Horace Greeley to "Go West, young man." This influx spurred the county to construct a harbor at San Pedro, 40km (25mi) south of city hall starting in 1999, with the first wharf opening in 1914. That same year, the Panama Canal was completed, effectively bringing San Pedro 8000 miles closer to the Atlantic seaboard, and rendering San Pedro the busiest harbor on the West Coast.

This, coupled with another invaluable development - the discovery of oil, cause the population to soar to one million by 1920, and two million by 1930. During WWI, the Lockheed brothers and Donald Douglas established aerospace plants in the area, and by WWII the aviation industry employed enough people to lift Los Angeles out of the Depression. Aviation employees flooded the county, generating a real estate boom, and bringing capital to the region as well as new suburbs south of Los Angeles. 

The influx generated by the newly created entertainment industry proved even greater than that of the aviation industry. Ever since the studios first landed in Los Angeles, the city has raced to live up to the hype created by 'the industry'. That image proved to be timeless and helped lure two new immigrant groups: the eccentric artisan and the fashionable hedonist, both drawn by the broad sandy beaches and the temptation of living the Hollywood lifestyle. Modern day would-be Angelenos still come for the very same reasons. Today, Los Angeles County has 88 cities and more than 140 unincorporated communities, and continues to thrive as one of the top places to live in the United States.