Alamo is an unincorporated community and census-designated place (CDP) in Contra Costa County, California, in the United States. It is a suburb located in the San Francisco Bay Area's East Bay region, approximately 28 miles (45 km) east of San Francisco. Alamo is equidistant from the city of Walnut Creek and the incorporated town of Danville. As of the 2020 census, the population was 15,314.

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.