What are the Hills Flat, California Zip Codes for 2020, 2019Primary Zip Codes for Hills FlatZip CodePrimary CitySecondary City95945Grass ValleyHills Flat, Alta Hill, Bear River Pines, Boston Ravine, Glenbrook Heights, La Barr Meadows, Peardale, Spring Hill, Sunset View, Union Hill, Willaura Estates, Alta SierraCities sharing Zip Codes with Hills FlatZip CodePrimary CitySecondary CityMore Information95945Grass ValleyAlta Hill95945Grass ValleyBear River Pines95945Grass ValleyBoston Ravine95945Grass ValleyGlenbrook Heights95945Grass ValleyHills Flat95945Grass ValleyLa Barr Meadows95945Grass ValleyPeardale95945Grass ValleySpring Hill95945Grass ValleySunset View95945Grass ValleyUnion Hill95945Grass ValleyWillaura Estates95945Grass ValleyAlta Sierra Alta Sierra population stats Advertisements