West Sacramento (also known as West Sac) is a city in Yolo County, California. It is contiguous with Sacramento, but is separated by the Sacramento River which is also the county line, so West Sacramento is in a different county from that of Sacramento. It is a fast-growing community; the population was 48,744 at the 2010 census, up from 31,615 at the 2000 census. The traditional industrial center of the region since the Gold Rush era, West Sacramento is home to a diverse economy and is one of the area's top four employment centers.