Marconi Wireless-Synanon Tomales Bay Headquarters Historic District (Boundary Increase)

18500 CA 1, Marshall, California. County/parish: Marin.

Added to the National Register of Historic Places January 31, 2025. NRIS 88003223.

Also known as:

• Marconi Property
• Station KPH- Marconi Wireless Telegraph Company of America Historic District (Old Name)
• Synanon “Bay Ranch”

National Park Service documentation: https://catalog.archives.gov/id/123859717

LC