Martinez (Spanish: Martínez) is a city in and the county seat of Contra Costa County, California, United States, in the East Bay region of the San Francisco Bay Area. Located on the southern shore of the Carquinez Strait, the city's population was 37,287 at the 2020 census. The city is named after Californio ranchero Ygnacio Martínez, having been founded on his Rancho El Pinole. Martinez is known for its historic center and its waterfront.
History
thumb|left|The [[Vicente Martínez Adobe, built in 1849 by a son of Ygnacio Martínez, is the oldest building in Martinez.]]
thumb|left|The [[John Muir National Historic Site, home of famed naturalist John Muir from 1880 until his death in 1914]]
The beautiful, lush Alhambra Valley was probably a seasonal foraging “pantry” for the stable population of the Karkines Indians. The Karkines are a part of the Ohlone (Costanoan) Indian group.
In 1824, the western side of Martinez, Alhambra Valley was included in the Rancho El Pinole Mexican land grant to Ygnacio Martínez. East of these lands was the Rancho Las Juntas, a grant made to Irish born William Welch in 1844; his land lay between the lands of Martinez and Pacheco.
In 1847, Dr. Robert Semple contracted to provide ferry service from Martinez to Benicia, which for many years was the only crossing on the Carquinez Strait. It became the county seat in 1850, but could not incorporate at the time because it lacked the 200 registered voters required, and would not become a city until 1876.
Martinez was the home of naturalist John Muir from 1880 until his death in 1914. He was buried about a mile south of the building that is now the John Muir National Historic Site. Also nearby is the Vicente Martinez Adobe, built in 1849 by the son of Ygnacio Martinez.
The first oil refinery in the Martinez area was built in 1904 at Bull's Head Point, a then-unincorporated waterfront area two miles east of the downtown district. That area soon became known as Mococo, following the 1905 arrival of a smelting works, operated by the Mountain Copper Company (Mo Co Co).
thumb|left|The historic [[Contra Costa County Courthouse was built in 1901.]]
That first facility, operated by the Bull's Head Oil Company, was followed in 1908 by a test refinery built by the Pacific Coast Oil Company. Shortly thereafter, Pacific Coast became part of Standard Oil (now Chevron), and consolidated their oil refining operations in the Point Richmond, Hercules, Rodeo waterfront corridor some to the west of Martinez.
In 1913, the Golden Eagle facility became the third oil refinery to be built in the area. It was located in the newly created company town of Avon, immediately to the East of Martinez. A fourth refinery, built by the Shell Oil Company on land adjacent to the Martinez City limits, went online in January 1916. The Shell Oil refining facility is still operational today (Currently owned by PBF Energy), maintaining the city's position as a significant petroleum processing center. The Golden Eagle Refinery (currently owned by Marathon Petroleum Company) was idled in April 2020 as a response to lower petroleum demand during the COVID-19 pandemic.
Folk etymology in Martinez claims the invention of the Martini cocktail and that it is named for the city.
Geography
thumb|left|The [[Benicia-Martinez Bridge, which crosses the Carquinez Strait, connects Martinez in the south to Benicia in the north (top).]]
According to the United States Census Bureau, the city has a total area of , of which (7.36 percent) is covered by water. Martinez's location at the east end of the Carquinez Strait as it widens to Suisun Bay includes dramatic water views stretching to the Sierra range. From surrounding ridge tops views stretch to nearby Mount Diablo, Mount Saint Helena, Mount Tamalpais, and others.
thumb|right|280px|Aerial view of Martinez (bottom); [[Benicia, California|Benicia is located across the Carquinez Strait (top).]]
Martinez is one of the only two places in the Bay Area, the other being Golden Gate Bridge, where the Bay Area Ridge Trail and the San Francisco Bay Trail converge. The Bay Trail is a planned recreational corridor that, when complete, will encircle San Francisco and San Pablo bays with a continuous network of bicycling and hiking trails. It will connect the shoreline of all nine Bay Area counties, link 47 cities, and cross the major toll bridges in the region, including the Benicia–Martinez Bridge. To date, approximately of the alignment—over half the Bay Trail's ultimate length—have been completed. The Bay Area Ridge Trail ultimately will be a 500+ mile trail encircling the San Francisco Bay along the ridge tops, open to hikers, equestrians, mountain bicyclists, and outdoor enthusiasts of all types. So far, over of trail have been dedicated for use. East Bay Regional Park District's Iron Horse Regional Trail will join the Bay Trail along the waterfront, and the Contra Costa Canal Trail threads through the city from Pleasant Hill to the south.
Climate
Martinez has a mild Mediterranean climate (Köppen climate classification: Csa/b). Summers are warm and dry, with some morning fog during sea breezes. The maritime influence is much less significant than in other parts of the Bay Area that are closer to the Pacific, which causes very high daytime averages compared to San Francisco and Oakland in summer. However, nights normally cool off significantly, which results in daytime highs around and nighttime lows of during July and August. Winters are wet and cool with occasional frost. The majority of the city is within a USDA hardiness zone of 9b.
Demographics
thumb|left|View from the Martinez Marina