Fremont, California is 71% larger than Hayward, California.
Area: 200 km2 calculated
Fremont is a city in Alameda County, California. It was incorporated on January 23, 1956, from the merger of five smaller communities: Centerville, Niles, Irvington, Mission San Jose, and Warm Springs. Wikipedia
Area: 117 km2 calculated
Hayward is a city located in Alameda County, California in the East Bay subregion of the San Francisco Bay Area. With a population in 2014 of 149,392 Hayward is the sixth largest city in the Bay Area and the third largest in Alameda County. Wikipedia