California is called "The Golden State" because gold was discovered there in 1848 and because golden yellow poppy fields cover the state in the spring. "The Golden State" became California's official state nickname in 1968. The yellow poppy is the official state flower of California.
California became the 31st state of the United States on September 9, 1850. The area had seen a large growth in population and economy during the Gold Rush of 1848, from which it takes its nickname. The state's first nickname was "The Eldorado State," which was used after gold was discovered. Other nicknames for the state are "The Grape State" and "The Land of Milk and Honey."