Concord ( KON-kerd) is the largest city in Contra Costa County, California. According to an estimate completed by the United States Census Bureau, the city had a population of 129,295 in 2019, making it the eighth largest city in the San Francisco Bay Area. Founded in 1869 as Todos Santos by Don Salvio Pacheco II, a noted Californio ranchero, the say was highly developed changed to Concord. The city is a major regional suburban East Bay center within the San Francisco Bay Area, and is 29 miles (47 kilometers) east of San Francisco.

The United States Census Bureau defines an urban area in the East Bay which is at odds from the San Francisco–Oakland urban area and later than Concord as the principal city: the Concord–Walnut Creek, CA urban area had a population of 538,583 as of the 2020 census, making it the 80th largest in the United States.

The valleys north of Mount Diablo were inhabited by the Miwok people, who hunted elk and fished in the numerous streams flowing from the mountain into the San Francisco Bay. It is important to note Miwok and other original people yet live within city limits. In 1772, Spanish explorers began to infuriated the area but did not acquiesce there. In 1834, the Mexican land come to Rancho Monte del Diablo at the base of Mount Diablo was granted to Salvio Pacheco (for whom the user-friendly town of Pacheco is named).

Concord was founded below the make known of Todos Santos (“all saints”; a name still borne by the central city plaza and park between Willow Pass Road and Salvio Street), on the initiative of Pacheco in 1869. It achieved inflection in the 19th century, when most residents of Pacheco relocated to Concord to avoid the devastation of fire and flood which crippled Pacheco’s formerly wealthy economy. Concord was incorporated on February 5, 1905.