1542
First European contact with the area; Juan Rodriguez Cabrillo enters San Diego Bay.

1602
Second European contact; Sebastian Vizcaino maps and names San Diego Bay.

1769
Presidio of San Diego and Mission San Diego de Alcala are established.

1821
Mexico gains its independence from Spain; San Diego becomes part of the Mexican province of Alta California.

1825
San Diego becomes the unofficial capital of Alta California.

1835
Juan Maria Osuna is elected the first alcalde (mayor) of San Diego.

1836
Alta California is disestablished and merged with Las Californias.

1840
Population: 140

1847
Mexican American War.
Treaty of Cahuenga ceasefire is signed on January 13, 1847.

Siete Leyes repealed, reestablishing the Alta California and Baja California territories.

1848
Treaty of Guadalupe Hidalgo (proclaimed July 4, 1848) transfers San Diego and all of Alta', California to the United States as part of the Mexican Cession Territory.

1850
California is admitted to the United States; San Diego becomes the seat of San Diego County; San Diego is granted a city charter by the California legislature.

1851
Herald newspaper begins publication.
The Movement for State Division of California convenes In San Diego to discuss the secession of Southern California from the rest of California as the proposed state of Colorado.

1852

U.S. Army sets aside southern part of Point Lorna for military use. It is later developed into Fort Rosecrans.

1855
Point Lorna Lighthouse is built.

1859
San Diego County votes to secede from California to form the Territory of Colorado, voting 207-24 in favor of secession.

1868
City reserves 1,400 acres of land as a City Park, now Balboa Park San Diego Union newspaper begins publication.

1870
The San Diego Chamber of Commerce established.

1871
City and county records are moved from Old Town to New Town, establishing New Town as the city's hub.

1872
San Diego is incorporated.

1880
Population: 2,637; county 8,018.

1881
The Sun newspaper begins publication.

1882
The San Diego Free Public Library is established.
The YMCA established.

1883-1886
John J. Montgomery makes successful flights with manned gliders at Otay Mesa, the first controlled flights in a heavier than air flying machine in America.

1885
Santa Fe Railway begins operating.

1886
Horse-drawn streetcar line is established downtown.

1887
San Diego Daily Bee newspaper begins publication.

National City & Otay Rail Road begins operating.

Electric streetcar line is established between Downtown and Old Town.

1888
Sweetwater Dam is completed.
City rechartered; mayor-council form of government adopted.

1890
Population: 16,159.

1892
San Diego Electric Railway begins operating.

1895
Evening Tribune newspaper begins publication.

1897
San Diego State Normal School (now San Diego State University) is established.

1900
Population: 17,700.

1903
Marine Biological Association of San Diego founded; now Scripps Institution of Oceanography.

1904
Navy Coaling Station established on Point Lorna; first navy establishment in the city.

William Smythe founds San Ysidro, later (1957) it is annexed to San Diego.

1910
City Park renamed Balboa Park.
U.S. Grant Hotel built.
Population: 39,578; county 61,665.

1913
Cabrillo National Monument is established.

May: San Diego stadium opens; now Balboa Stadium.

1916
San Diego Zoo established.

1917
Army Camp Kearny is established.

1919
San Diego and Arizona Railway is completed.

1920
Population: 74,683; county 112,248.

1921
U.S. Marine Corps training base is commissioned.

1922
U.S. Navy Destroyer Bl'Ise, San Diego is established; now Naval Base San Diego.

1923
Naval Training Center San Diego is established.

San Diego annexes East San Diego.

1924
The first United States aircraft carrier, USS Langley begins operating out of North Island.

1925
U.S. Naval hospital is built.

1926
Star of India is towed into San Diego harbor; later renovated and opened as a museum ship.
Fine Arts Gallery opens; now the San Diego Museum of Art.

1927
Charles Lindbergh's plane The Spirit of Sf. Louis is designed and built in San Diego by the Ryan Airline Company.

1928
San Diego Municipal Airport is dedicated as Lindbergh Field.

1930
Population: 147,995; county 209,659.

1931
San Diego State College dedicated; formerly San Diego State Normal School, now San Diego State University.
New city charter adopted under a council-manager form of government.

1936
San Diego Padres established as a minor league team within the Pacific Coast League.

Roman Catholic Diocese of San Diego is established.

1937
U.S. Coast Guard Air Station San Diego commissioned.

1938
San Diego Civic Center dedicated; now the San Diego County Administration Center.

1940
Population: 203,341; county 289,348.

1941
Consolidated Aircraft becomes San Diego's largest employer.

1942
Residents of Japanese decent are evicted from San Diego and relocated to internment camps by order of President Franklin D. Roosevelt. They are given three days to sell
their homes and other property.
U.S,. Marine Corps. Base Camp Pendleton is established.

1943
Consolidated Aircraft and Vuitee Aircraft merge to become Convair.
Camp Kearny recommissioned as Naval Auxiliary Air Station Camp Kearny and Marine Corps Air Depot Miramar

1945
Navy Electronics Laboratory established, now part of Space and Naval Warfare

Systems Center Pacific.

1946
Submarine Group San Diego established, now part of Naval Base Point Loma.

1948
Maritime Museum of San Diego is established.

1950
Population: 333,865; county 556,808.

1952
San Diego College for Women opens; now the University of San Diego.
Miramar Naval Air Station established.

1955
Journal of San Diego History begins publication.

1957
Fort Rosecrans is transferred to the U.S. Navy.

San Diego annexes San Ysidro.

1960
University of California, San Diego and Salk Institute for Biological Studies established.

Population: 573,224; county 1,033,011.

1961
San Diego Chargers move to San Diego after one season in Los Angeles.

1962
San Diego annexes Rancho Bernardo.

1963
Navy Submarine Support Facility is established, now part of Naval Base Point Loma.

San Diego Aerospace Museum is established.

1964
SeaWorld San Diego opens.

San Diego annexes the rest of northern San Diego.

1966
San Diego International Sports Center opens, later known as San Diego Sports Arena, iPay One Center, and Valley View Casino Center, now Pechanga Arena.
San Diego County Comprehensive Planning Organization established, now San Diego Association of Governments (SANDAG).

1967
San Diego Stadium opens, later known as Jack Murphy Stadium, Qualcomm Stadium, and SDCCU Stadium.
Historical Resources Board established.

1969
San Diego Padres is established as a Major League Baseball team.

San Diego–Coronado Bridge constructed.

TOPGUN United States Navy Strike Fighter Tactics Instructor program is established at Miramar Naval Air Station.

1971
San Diego Rockets relocate to Houston to become the Houston Rockets.

1972
NBA Buffalo Braves relocate to San Diego to become the San Diego Clippers.

1980
Population: 875,538; county 1,861,846.

1981
San Diego Trolley begins operations.

1984
San Diego Clippers relocate to Los Angeles becoming the Los Angeles Clippers.

1987
Asian Pacific Thematic Historic District is designated by the city.

1989
San Diego Convention Center opens.

1990
Population: 1,110,549.

1996
1996 Republican National Convention held.

1997
U.S. Navy Space and Naval Warfare Systems Command ("SPAWAR") headquarters relocated to San Diego.

1999
Legoland California opens in nearby Carlsbad.

2000
Population: 1,223,400.

2004
Petco Park opens.

USS Midway Museum opens on Embarcadero.

2005
Voice of San Diego begins publication.
San Diego Trolley Green Line opens in Mission Valley.

2006
San Diego reverts to a Mayor-council form of government on a five-year trial basis.
Form of government made permanent in 2010.

2010
Population: 1,307,402; metro 3,095,313.

2013
Little Saigon, San Diego is designated.

2015
Carlsbad desalination plant opens December 14, north of San Diego.

2016
San Diego Chargers relocate to Los Angeles, becoming the Los Angeles Chargers.

2017
San Diego Seals formed, joins the National Lacrosse League.

2020
Convoy (Pan Asian Cultural & Business Innovation) District is designated.

2021
SDCCU Stadium demolished.