Martinez, city, seat (1850) of Contra Costa county, western California, U.S. It lies on the south shore of Carquinez Strait (between Suisun and San Pablo bays) north of Oakland. It was named for Ignacio Martínez, commandant of the San Francisco presidio and grantee (1829) of the Rancho El Pinole, which was part of the original town site (laid out in 1849 by Colonel William E. Smith). Martinez was originally a trading post, and it became a shipping centre after gold was discovered in the vicinity. In the late 19th century, the city was heavily settled by Italian immigrants, who developed a wine industry there that was later relocated to Napa Valley.
The completion of the Contra Costa Canal (1947) to its Martinez Reservoir terminus and the opening of the Benicia-Martinez Bridge (1962) across the strait (with construction of a new bridge begun in 1999) boosted the city’s port and industrial development (petroleum, chemicals, steel, and copper). Local attractions include the Martinez Museum and the Don Vicente Martinez Adobe (built 1849). Martinez is the birthplace of baseball player Joe DiMaggio. It is also said to be the birthplace of the martini (originally called the “Martinez Special” by a local bartender in 1849), though San Francisco and other cities also have made such claims. Carquinez Strait Regional Shoreline is a popular recreational spot, particularly for hikers. Benicia Capitol State Historic Park, the site of a former capital of California, is north of Martinez in Benicia, and John Muir National Historic Site preserves the last home of the naturalist. Inc. 1876. Pop. (2000) 35,866; (2010) 35,824.