1769 José Antonio Yorba, a young soldier in the Portolá overland expedition to Monterey, gets his first glimpse of what is today called Orange County.
1810 Rancho Santiago de Santa Ana granted to José Antonio Yorba and his nephew, Juan Pablo Peralta.
1820s Three adobe estancias constructed on bluffs overlooking the Santa Ana River to shelter wandering vaqueros.
1823 Mexico wins its independence from Spain.
1848 Mexico cedes to the United States that territory known today as the US Southwest, including all of California
1868 Rancho Santiago de Santa Ana partitioned into 73 parcels of various sizes. Further partitioning and sales continue for the rest of the century.
1886 Paularino agricultural colony established in the area along today’s Baker Street between Newport Blvd and Harbor Blvd.
1887 Boom town of Fairview springs up at what is now the intersection of Harbor Blvd and Adams Ave.
1889 Boom town of Fairview goes bust. Orange County secedes from Los Angeles County.
1891 Santa Ana and Newport Railroad begins service on tracks running down what is now Newport Blvd.
1890s Harper railroad siding established on what is now the west side of Newport Blvd opposite E 18th St.

Thurin railroad siding established between current day 22nd St and 23rd St.

1899 Santa Ana and Newport Railroad purchased by Southern Pacific.
1900-03 Drought drives most farming families, including the Harpers, off the mesa.
1906 First oil wells are drilled on the mesa, south of the present location of Newport Harbor High School.

Water reservoir built on 16th St between Orange Ave and Santa Ana Ave (present site of Heller Park).

La Habra Land and Water Company (Stephen Townsend, President) subdivides 1,700 acres of Newport Heights (now the Eastside) into five-acre farms, which are then promoted by the Townsend-Dayman Investment Company of Long Beach.

1907 Townsend subdivides Newport-Mesa Tract, in what is currently known as the Westside south of 19th St.

More oil wells go up in the northern part of Newport Heights, near 21st St and 22nd St and Irvine Ave.

1908 The new town of Harper’s first school opens in a remodeled farmhouse at what is now 17th St and Newport Blvd, near where the Harp Inn is today.

Harper’s first commercial building, the Ozment General Store, is built at the northeast corner of 18th St and Newport Blvd.

1909 Grocer Ozment named first postmaster for Harper.
1910 First commercial apple orchards planted by George Waterman and George Huntington.

New two-room schoolhouse opens at the southeast corner of 17th St and Orange Ave.

1913 Fairview Farms tract opened on the Westside, between 19th St and Wilson St. (N-S) and Newport Blvd and the Santa Ana River (E-W).
1915 First permanent church, the Harper Methodist Episcopal Church, is built at southwest corner of Center St and Newport Blvd.
1916 Worst flooding by Santa Ana River since 1884.
1920 Newport Heights Co-operative Association, Fairview Farms Association and Newport Mesa Association offer a $25 prize for a new name for Harper. Former schoolteacher Alice Plumer wins with her entry, Costa Mesa.

Electricity arrives on the mesa for the first time.

1922 Bumper apple crop.

Costa Mesa Bank, the Costa Mesa branch of Bank of Balboa, opens.

1923 First sidewalks installed downtown.

First local newspaper, the Costa Mesa Herald begins operation (later this paper evolved into the Daily Pilot).

Costa Mesa Grammar School opens at northwest corner of 19th St and Newport Blvd.

1925 Fred Bush elected as Costa Mesa’s first fire chief.

Frank Vaughn hired as Costa Mesa’s first police officer.

Changes in weather patterns and rise of pests leads to decline of apple cultivation on the mesa.

1928 Santa Ana’s attempt to annex part of Costa Mesa defeated by five to one.
1930 Monte Vista school opens at Center St and Placentia Ave to provide “separate but equal” facilities for Costa Mesa’s Mexican children.

Newport Harbor High School completed. Rivalry emerges between Costa Mesa students and Newport Beach students. The appellation “Goat Hill” is born. So is the name “Mackerel Flats.”

Great Depression begins.

1932 Costa Mesa branch of the Bank of Balboa closes.
1933 Long Beach earthquake devastates downtown Costa Mesa.

Southern Pacific branch line running down Newport Blvd is abandoned.

1934 Len Martin establishes the Costa Mesa Globe, then buys the Herald to combine it with his own paper as the Costa Mesa Globe-Herald.
1936 Early NIMBYs defeat plans to construct state prison farm off what is now Harbor Blvd.
1938 Fatal floods rampage through Orange County.

First annual Costa Mesa Scarecrow Carnival.

1940 Costa Mesa Scarecrow Carnival makes national news after local party animals kidnap a lady scarecrow and abandon her in Tijuana.
1941 Groundbreaking for United States Air Corps Replacement Training Center.

United States enters World War II.

1942 United States Air Corps Replacement Training Center redesignated the Santa Ana Army Air Base. It eventually grows to encompass 1,337 acres between Newport Blvd and Harbor Blvd where the Civic Center, Orange Coast College, Vanguard University and the Orange County Fairgrounds are today.
1945 Santa Ana Army Air Base closed.
1946 War Assets Administration sells Santa Ana Army Air Base plot to Orange Coast Junior College District.

First Lions Club Costa Mesa Fish Fry.

Sky Harbor airport opens along 19th St west of Placentia.

1948 Orange Coast Junior College opens (now Orange Coast College).

Mesa Theatre cinema opens on Newport Blvd near 19th St, where Mother’s Market is today.

Costa Mesa’s first park, Lions Park, opens.

First local incorporation effort fails.

1949 Paulo Drive-in Theatre opens on northwest corner of Newport Blvd and Paularino St.
1950 Southern California Bible College opens (now Vanguard University).
1953 Amid annexation efforts by Santa Ana and Newport Beach, City of Costa Mesa is incorporated, encompassing most of the current city south of Mesa Dr and Wilson St, 3½ square miles.

Sky Harbor airport demolished to make way for residential development.

1961 Santa Ana Army Air Base gets a mention in Joseph Heller’s bestselling novel Catch-22.
1966 Costa Mesa Historical Society established to transform the restored Diego Sepulveda Adobe into a museum and provide docents.
1967 New Civic Center completed on Fair Drive.

Initial phases (May Company) of South Coast Plaza completed.

1968 San Diego Freeway passes through north Costa Mesa.
1972 City of Costa Mesa forms Redevelopment Agency
1978 South Coast Repertory relocates to newly-opened 4th step theater in Town Center
1983 Courtyards shopping center redevelopment opens in downtown.
1986 Orange County Performing Arts Center opens in Town Center
1991 Triangle Square redevelopment opens in downtown.
1992 55 Freeway extended to 19th St.
1998 Fairview Park Master Plan adopted by Costa Mesa City Council
1999 City reaches 97.3% build-out.  Only 218 acres remain for initial development out of a total of 8100 acres.
2006 The Renée and Henry Segerstrom Concert Hall opens in Town Center
2012 Measure V, to convert Costa Mesa to a charter city, fails to pass in the Nov. 6 general election, 13,806 yes to 20,529 no