Napa County Real Estate View 390 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 Contra Costa CountySolano CountyNapa CountySonoma CountyMarin CountySacramento CountyPlacer CountyEl Dorado County