About Martinez

Martinez is a city and the county seat of Contra Costa County, California, United States. The population was 35,824 at the 2010 census. The downtown is notable for its large number of preserved old buildings. Martinez is located on the south side of the Carquinez Strait in the San Francisco Bay Area, directly facing the city of Benicia.

In 1824 the Alhambra Valley was included in the Rancho El Pinole Mexican land grant to Ygnacio Martínez. 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. By 1849, Martínez served as a way station for the California Gold Rush. The town was laid out in 1849 by Col. William M. Smith and named for Martinez. It became the county seat in 1850, but could not incorporate at the time because it lacked the 200 registered voters required, and only became a city in 1876.

The first post office opened in 1851.

In 1860, Martinez played a role in the Pony Express, where riders would take the ferry from Benicia (particularly if they missed the steamer in Sacramento). In 1915, Shell Oil Company built an oil refinery in unincorporated Martinez, which sparked a building boom in the area. A second area refinery (presently owned by Tesoro Petroleum Co.), together with the Shell facilities, help make Martinez a significant petroleum processing center and port. The oil refineries in and near Martinez can still be seen today from Interstate 680.

Although the common perception of Martinez is that of a refinery town, given the view from Highway 680 across the Shell refinery from the Martinez-Benicia Bridge, the city is in fact largely surrounded by water and regional open space preserves. The Martinez-Benicia Bridge carries Highway 680 across the eastern end of the Carquinez Strait to Solano County. The city can be defined as a more densely built downtown valley threaded by Alhambra creek and north of Highway 4. Suburban areas stretch south of Highway 4 to join the neighboring city of Pleasant Hill. Unincorporated areas include the rural Alhambra Valley and the Franklin Canyon area.