Pittsburg is a city in Contra Costa County, California, United States. It is an industrial suburb located on the southern shore of the Suisun Bay in the East Bay region of the San Francisco Bay Area, and is part of the Sacramento–San Joaquin River Delta area, the Eastern Contra Costa County area, and the San Francisco Bay Area. The population was 76,416 at the 2020 United States Census.

Contra Costa County is a county located in the U.S. state of California, in the East Bay of the San Francisco Bay Area. As of the 2020 United States Census, the population was 1,165,927. The county seat is Martinez. It occupies the northern portion of the East Bay region of the San Francisco Bay Area and is primarily suburban. The county's name refers to its position on the other side of the bay from San Francisco. Contra Costa County is included in the San Francisco–Oakland–Berkeley, CA Metropolitan Statistical Area.