San Francisco is 37% larger than Vallejo, California.
Area: 122 km2 calculated
San Francisco, officially the City and County of San Francisco, is the cultural center and a leading financial hub of the San Francisco Bay Area and Northern California. Wikipedia
Area: 89 km2 calculated
Vallejo is the largest city in Solano County, California, United States. The population was 115,942 at the 2010 census. It is the tenth most populous city in the San Francisco Bay Area, and is located on the northeastern shore of San Pablo Bay. Vallejo is named for General Mariano Guadalupe Vallejo. Wikipedia