Concord (/ˈkɒŋkərd/ kong-kərd; formerly Todos Santos[10]) is the largest city in Contra Costa CountyCalifornia, in the United States. At the 2010 census, the city had a population of 122,067.[11] Founded in 1869 as the community of Todos Santos by Salvio Pacheco, the name was changed to Concord within months. The city is a major regional suburban East Bay center within the San Francisco Bay Area, and is 31 miles (50 km) east of San Francisco.