when did california became a state of the union
California What is now California was first settled by various Native Californian tribes before being explored by a number of European expeditions during the 16th and 17th centuries. The Spanish Empire then claimed it as part of Alta California in their New Spain colony. The area became a part of Mexico in 1821 following its successful war for independence but was ceded to the United States in 1848 after the Mexican–American War. The western portion of Alta California then was organized and admitted as the 31st state on September 9, 1850. The California Gold Rush starting in 1848 led to dramatic social and demographic changes, with large-scale emigration from the east and abroad with an accompanying economic boom.
California Republic In June 1846, thirty-three American immigrants in Alta California rebelled against the Mexican department's[notes 1][2] government. The immigrants had not been allowed to buy or rent land and had been threatened with expulsion from California because they had entered illegally without official permission.[3][4] Mexican officials were concerned about a coming war with the United States coupled with the growing influx of Americans into California. The rebellion was soon overtaken by the beginning of the Mexican–American War.