- Where is Adelphia located?
- Adelphia is in Napa Valley, United States (P.O. Box 660, Napa CA 94559 (707) 257-9500 | www.cityofnapa.org Page 3 City of Napa Response to 2..., Superior Court of Napa County (.gov), Zip Code List County - Napa County, California, Table_title: Zip Code List County - Napa County, California Table_content: header: | Zip Code | City | County | row: | Zip Code: 94558 | City: Spanish Flat | Co..., ciclt.net, Show more, Web results, Latitude and Longitude Finder).