 Avenal owes its origin to the discovery of oil on 4 October 1928, in the adjacent Kettleman Hills.Avenal was the site of a "tent city" as the boom started, but foresight made the boom orderly, so that by 1940 Avenal was the second largest town in Kings County with a population of 4,600.Growth continues today to include a more diversified economy based on oil, agriculture, and the service industry.