1542 Navigator João Rodrigues Cabrilho of Portugal arrives at what is now San Diego, California, United States.
1579 Sir Francis Drake claims a land he calls ''Nova Albion'' (modern California) for England.
1769 An expedition led by Gaspar de Portolà establishes a base in California and sets out to find the Port of Monterey (now Monterey, California).
1769 Father Junipero Serra founds California's first mission, Mission San Diego de Alcalá. Over the following decades, it evolves into the city of San Diego.
1846 The Donner Party of pioneers departs Springfield, Illinois, for California, on what will become a year-long journey of hardship, cannibalism, and survival.
1846 Mexican-American War: American troops occupy Monterey and Yerba Buena, thus beginning the U.S. conquest of California.
1847 The Treaty of Cahuenga ends the Mexican-American War in California.
1847 John C. Fremont is appointed Governor of the new California Territory.
1847 Yerba Buena, California is renamed San Francisco.
1848 Mexican-American War: Mexico ratifies the Treaty of Guadalupe Hidalgo thus ending the war and ceding California, Nevada, Utah and parts of four other modern-day U.S. states to the United States for $15 million USD.
1848 California Gold Rush: the ''New York Herald'' breaks the news to the East Coast of the United States of the gold rush in California (although the rush started in January).
1848 California Gold Rush: In a message before the U.S. Congress, US President James K. Polk confirms that large amounts of gold had been discovered in California.
1850 California is admitted as the thirty-first U.S. state.
1857 The Fort Tejon earthquake of California occurs, registering an estimated magnitude of 7.9.
1864 U.S. President Abraham Lincoln grants Yosemite Valley to California for "public use, resort and recreation".
1878 In California, the poet and American West outlaw calling himself "Black Bart" makes his last clean getaway when he steals a safe box from a Wells Fargo stagecoach. The empty box will be found later with a taunting poem inside.
1880 Seven people are killed in the Mussel Slough Tragedy, a gun battle in California
1890 The Tournament of Roses Parade in Pasadena, California, is first held.
1891 In the U.S. state of California, Stanford University opens its doors.
1902 "Electric Theatre", the first full-time movie theater in the United States, opens in Los Angeles, California.
1906 The 1906 San Francisco earthquake and fire destroys much of San Francisco, California.
1911 Ishi, considered the last Native American to make contact with European Americans, emerges from the wilderness of northeastern California.
1913 Death Valley, California hits 134 °F (
1913 A major labour dispute, known as the Wheatland Hop Riot, starts in Wheatland, California.
1918 The Twin Peaks Tunnel in San Francisco, California begins service as the longest streetcar tunnel in the world at 11,920 feet (3,633 meters) long.
1923 Honda Point Disaster: nine US Navy destroyers run aground off the California coast. Seven are lost, and twenty-three sailors killed.
1928 In California, the St. Francis Dam fails, killing over 600 people.
1931 The Congress of the United States approves the construction of the San Francisco – Oakland Bay Bridge by the state of California.
1935 Amelia Earhart is the first person to fly solo from Hawaii to California.
1936 In California, the San Francisco – Oakland Bay Bridge opens to traffic.
1937 In California, the Golden Gate Bridge opens to pedestrian traffic, creating a vital link between San Francisco and Marin County, California.
1937 The Golden Gate Bridge in San Francisco, California, is officially opened by President Franklin D. Roosevelt in Washington, D.C., who pushes a button signaling the start of vehicle traffic over the span.
1940 California opens its first freeway, the Arroyo Seco Parkway.
1941 At California's March Field, Bob Hope performs his first USO show.
1942 World War II: The two-person crew of the U.S. naval blimp L-8 disappears without a trace on a routine anti-submarine patrol over the Pacific Ocean. The blimp drifts without her crew and crash-lands in Daly City, California.
1945 Fifty nations gather in San Francisco, California to begin the United Nations Conference on International Organizations.
1947 The brutalized corpse of Elizabeth Short ("The Black Dahlia") is found in Leimert Park, Los Angeles, California.
1947 In California, designer Howard Hughes performs the maiden (and only) flight of the Spruce Goose; the largest fixed-wing aircraft ever built.
1951 Treaty of San Francisco: In San Francisco, California, 48 nations sign a peace treaty with Japan in formal recognition of the end of the Pacific War.
1953 BCPA Flight 304 DC-6 crashes near San Francisco, California. Pianist William Kapell is among the 19 killed.
1955 The first Disneyland theme park, in Anaheim, California, opens to the public.
1965 The infamous first party between Ken Kesey's Merry Pranksters and motorcycle gang the Hells Angels takes place at Kesey's estate in La Honda, California introducing psychedelics to the gang world and forever linking the hippie movement to the Hell's Angels.
1967 The first Super Bowl is played in Los Angeles, California. The Green Bay Packers defeat the Kansas City Chiefs 35-10
1968 Vietnam War: 27 soldiers are arrested at the Presidio of San Francisco in California for their peaceful protest of stockade conditions and the Vietnam War.
1969 Two teens (one male, one female) are attacked at Blue Rock Springs in California. They are the second (known) victims of the Zodiac Killer. The male survives.
1969 Meredith Hunter is killed by the Hells Angels during a The Rolling Stones's concert at the Altamont Speedway in California.
1970 The Laguna Fire starts in San Diego County, California, burning 175,425 acres (710 km²).
1971 The 6.4 on the Richter Scale Sylmar earthquake hits the San Fernando Valley area of California.
1973 Tom Bradley is elected the first black mayor of Los Angeles, California.
1977 Oracle Corporation is incorporated in Redwood Shores, California, as Software Development Laboratories (SDL) by Larry Ellison, Bob Miner and Ed Oates.
1978 The Landsat 3 is launched from Vandenberg Air Force Base in California.
1978 PSA Flight 182, a Boeing 727-214, collides in mid-air with a Cessna 172 and crashes in San Diego, California, resulting in the deaths of 144 people.
1985 Serial killer Richard Ramirez, aka the "Night Stalker", commits the first two murders in his Los Angeles, California murder spree.
1986 Aeroméxico Flight 498 collides with a Piper PA-28 over Cerritos, California, killing 67 in the air and 15 on the ground.
1986 ''Voyager'', piloted by Dick Rutan and Jeana Yeager, lands at Edwards Air Force Base in California becoming the first aircraft to fly non-stop around the world without aerial or ground refueling.
1993 Savings and loan crisis: The United States Senate Ethics Committee issues a stern censure of California senator Alan Cranston for his "dealings" with savings-and-loan executive Charles Keating.
2002 2003 California recall: Then Governor of California Gray Davis announces that the state would face a record budget deficit of $35 billion, roughly double the figure reported during his reelection campaign one month earlier.
2003 2003 invasion of Iraq: In what becomes known as the "Mission Accomplished" speech, on board the {{USS|Abraham Lincoln|CVN-72|6}} (off the coast of California), U.S. President George W. Bush declares that "major combat operations in Iraq have ended".
2003 The Cedar Fire, the second-largest fire in California history, kills 15 people, consumes 250,000 acres (1,000 km²), and destroys 2,200 homes around San Diego.
2004 The city of San Francisco, California begins issuing marriage licenses to same-sex couples in response to a directive from Mayor Gavin Newsom.
2007 The Angora Fire starts near South Lake Tahoe, California, destroying over 200 structures in its first 48 hours.
2008 Proposition 8 passes in California, representing the first ever elimination of an existing right to marry for LGBT couples.
2010 California's Proposition 8, the ballot initiative prohibiting same-sex marriage passed by the state's voters in 2008, was overturned by Judge Vaughn Walker in the case Perry v. Schwarzenegger.