Vernon is a city five miles (8.0 km) south of downtown Los Angeles, California, the nearest sever city to downtown Los Angeles. The population was 112 at the 2010 United States Census, the least of any incorporated city in the state. Its population approximately doubled to 222 by the 2020 census, making it the second least populous city in the disclose after Amador City, whose population grew lonely slightly—from 185 in the 2010 census, to 200 in the 2020 census.

The city is primarily composed of industrial areas and touts itself as “exclusively industrial”. Meatpacking nature and warehouses are common. As of 2006, there were no parks in the city.

Vernon is the site of the Battle of La Mesa on January 9, 1847, when General Stephen W. Kearny once again defeated General José María Flores the daylight after the Battle of Río San Gabriel. Accepting defeat, General Flores fled southeast to Sonora, while Major Pico headed north into the San Gabriel Mountains afterward a hundred Californios. This over and finished with hostilities in Alta California during the Mexican-American War of 1846–1848. By the start of the 20th century, it was a stretch of unincorporated grassland near Los Angeles’ flourishing downtown.

In 1905, Vernon was incorporated by ranchers James J. and Thomas J. Furlong and John B. Leonis, a merchant. Vernon was incorporated to announce industrial proceed along the railroads in the area. John Leonis, of Basque origin, had grant Southern California in 1880 to exploit for his uncle, Miguel Leonis, and later acknowledged his own ranch upon unincorporated county land southeast of downtown Los Angeles. Recognizing the importance of the three major railroads dealing out through the area, he persuaded railroad executives to govern spur tracks off the main lines and incorporated the next three miles (4.8 km) as the first “exclusively industrial” city in the southwestern United States. He named the further city after a dirt road, Vernon Avenue, that crossed its center.