Napa County Real Estate View 359 listings HomeGuidesNapa County Napa County is north of San Francisco, in California. It’s known for hundreds of hillside vineyards in the Napa Valley wine region. In the city of Napa, Oxbow Public Market features regional gourmet food. Guides Sacramento CountyPlacer CountyEl Dorado CountySolano CountyNapa CountySonoma CountyMarin CountyContra Costa County