Oakland, California is 87% larger than Concord, California.
Area: 80 km2 calculated
Concord is the largest city in Contra Costa County, California, in the United States. At the 2010 census, the city had a population of 122,067. Founded in 1869 as the community of Todos Santos by Salvio Pacheco, the name was changed to Concord within months. Wikipedia
Area: 150 km2 calculated
Oakland is a major West Coast port city in the U.S. state of California. The Port of Oakland is the busiest port for San Francisco Bay and all of Northern California. Wikipedia