Hayward is a city in Alameda County, California, United States, in the East Bay subregion of the San Francisco Bay Area. With a population of 162,954 as of 2020, Hayward is the sixth largest city in the Bay Area, and the third largest in Alameda County. Hayward was ranked as the 36th most populous municipality in California. It is included in the San Francisco–Oakland–San Jose Metropolitan Statistical Area by the US Census. It is located primarily between Castro Valley, San Leandro and Union City, and lies at the eastern terminus of the San Mateo–Hayward Bridge.