Vernon is a city five miles south of downtown Los Angeles, California, the nearest separate city to downtown Los Angeles. The population was …Vernon is a city five miles south of downtown Los Angeles, California, the nearest separate 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 nearly doubled to 222 by the 2020 census, making it the least populous city in Southern California, and the second least populous city in the state after Amador City, whose population grew only slightly—from 185 in the 2010 census, to 200 in the 2020 census.