Hayward ( ; formerly Haywards , Haywards Station , and Haywood ) is a city located in Alameda County , California in the East Bay subregion of the San Francisco Bay Area . With a 2014 population of 149,392 , Hayward is the sixth largest city in the Bay Area and the third largest in Alameda County . Hayward was ranked as the 37th most populous municipality in California . It is included in the San Francisco – Oakland – Fremont Metropolitan Statistical Area by the US Census . It is located primarily between Castro Valley and Union City , and lies at the eastern terminus of the San Mateo – Hayward Bridge . The city was devastated early in its history by the 1868 Hayward earthquake . From the early 20th century until the beginning of the 1980s , Hayward 's economy was dominated by its now defunct food canning and salt production industries
1868 Hayward earthquake
1868 Hayward earthquake
Hayward, California