The following outline is provided as an overview of and topical guide to the U.S. state of California:
California is the most populous and the third most extensive of the 50 states of the United States of America. California is home to Los Angeles, San Francisco, San Diego, and Sacramento, respectively the 2nd, 6th, 17th, and 23rd most populous metropolitan areas of the United States.
California borders the North Pacific Ocean and Baja California in the Southwestern United States. California includes both Mount Whitney, the highest (4,421 m) mountain peak in the contiguous United States, and Death Valley, the lowest (−86 m) and hottest (56.7 °C) place in North America. California joined the Union as the 31st state on September 9, 1850.