Contra Costa County has always been one of the hardest counties in the Bay Area to define. Some define it by its largest city, Concord – known for its direct view of Mt Diablo, thriving Latinx community, and multiple stops on the BART line. Others think of old, industrial Contra Costa – the part of the county stretching from San Pablo Bay in Richmond to the Carquinez Strait in Martinez – with its shoreline, military history and the majority of the Bay’s refineries.