Homes For Sale, Granite Bay Granite Bay is a census-designated place in Placer County, California, United States. It is part of the Sacramento–Arden-Arcade–Roseville Metropolitan Statistical Area. The population was 20,402 at the 2010 census, up from 19,388 at the 2000 census. The ZIP code is 95746 or 95661. Sorry we are experiencing system issues. Please try again.