Latinos make up at least 20% of the San Francisco Bay Area. Many live in San Mateo, Redwood City, Alameda, Contra Costa and Santa Clara counties, as well in San Francisco. The Napa Valley and Salinas Valley have predominantly Latino communities established by migrant farm workers. San Jose is about 30–35 percent Latino, the largest Latino community in northern California, while the Mission District, San Francisco and Lower/West Oakland have barrios established by Mexican and Latin American immigrants. The Mexican American communities of East Los Angeles and Logan Heights, San Diego, as well the San Joaquin Valley are centers of historic Chicano and Latino cultures.