Between 1910 and 1950, Los Angeles County ranked number one among the most productive agricultural counties in the nation. At its peak during the 1920s, it produced nearly five percent of the value of all farm products sold by the nation's leading 100 agricultural counties. It had nearly twice the output as second-ranked Tulare County in California. Its products included not only Southern California's famous citrus crops, but also vegetables, tomatoes, berries, flowers and honey. Among the county's agricultural producers was a popular "small farm" movement where households with large lots did second-income farming from their gardens.
Los Angeles County's four-decade-long reign as "King of Agriculture" quickly came to an end after the end of World War II. The last year in which the U.S. Census of Agriculture ranked Los Angeles County as the most productive in the nation was 1949. As the region's post-war economy boomed with new industries, new residents poured into the county for the bounty of jobs. They demanded new homes, schools, shopping centers, parks and freeways. Productive farmland fell quickly to the bulldozer. By 1954, the county dropped to number 3 among America's most productive agricultural counties. By 1964, it dropped to number 8 and, by 1974, to number 38. The last year in which Los Angeles County ranked among the top 100 agricultural counties was 1992, ranking at number 92.
At the last U.S. census of agriculture in 2012, with almost $200 million worth of agricultural products sold, Los Angeles County ranked at 566 among 3,077 counties (number 32 among 58 California counties). There still remain spots of farming throughout the county, but, the larger share continues in the Antelope Valley.