Spanish explorer Juan Cabrillo was the first European to visit the area, stopping in present-day San Pedro in 1542, where he was greeted by native Tongva Indians.

It was over 225 years before the Spanish returned, coming to establish a Catholic mission in the area. Gaspar de Portola arrived in 1769 with two Franciscan priests, Father Junipero Serra and Father Juan Crespi. Passing through the area, they found a river which they named El Rio de Nuestra Señora La Reina de Los Angeles de Porciúncula, which means The River of Our Lady Queen of the Angels of Porciuncula, today's Los Angeles River.

Father Crespi found a place on the river bank that he thought would be good for a settlement, but in 1771, Father Serra commissioned two priests to build San Gabriel Mission elsewhere.

Spanish Governor Felipe de Neve recommended Crespi's location to King Carlos II of Spain, who ordered a town built on the site. In 1781, 44 settlers set out for El Pueblo de Nuestra Señora Reina de los Ángeles sobre El Rio Porciuncula, The Town of Our Lady Queen of the Angels on the Porciuncula River.

The small town soon became a cattle ranching center. Today, it is preserved as the El Pueblo de Los Angeles Historic Monument. Mexico gained independence from Spain in 1821, and former mission lands became civilian land grants. By 1850, California became a state. Los Angeles was incorporated in the same year. By the 1870s, the Central Pacific and Santa Fe Railroads had reached Los Angeles, and it boasted about 5,000 people.

Edward L. Doheny discovered oil near present-day Dodger Stadium in 1893. By the turn of the twentieth century, 100,000 people lived here and in 1923, Los Angeles produced one-quarter of the world's oil supply. Lack of water limited growth until a landmark public works project created an aqueduct to the city from northern California's Owens Valley.

In 1906, the city began annexing land, including a narrow strip that led south to the Port of Los Angeles. By 1910, the city covered 90 square miles.

Los Angeles became a center of the growing aviation industry during World War II. Workers streamed into the area to fill jobs at factories producing airplanes, supplies and war munitions. By 1950, the city was a financial giant and the center of the film industry. Construction boomed and the city continued to spread. The downtown Los Angeles skyline began to take shape when building height-limit laws were repealed in the 1970s.