Station KPH Operating Station
Also known as: Marconi Property
Why it's listed
This concrete and steel-frame building on a hill above Tomales Bay, near Marshall in Marin County, was built in 1913 as the operating building of the Marconi wireless receiving station later known as KPH. It measures about 84 by 41 feet and has a red tile hipped roof, a basement with thick concrete walls, and plain, utilitarian design. It originally held eight rooms for receiving equipment and staff offices, plus an open veranda on the bay side. The station, built by the J.G. White Engineering Company and dedicated in September 1914, worked with a transmitting station at Bolinas to connect California with Hawaii and, through Hawaii, Japan. It also handled ship-to-shore traffic over the Pacific. The Navy took it over in 1917, and the Radio Corporation of America ran it from 1920 until radio operations moved in 1931. The site was chosen because it was barren and free of vegetation that could interfere with reception. Later uses include residential use, and the veranda has since been enclosed.
Significance in brief: The nomination argues national significance in communications because Station KPH made trans-Pacific radio communication possible. With its Bolinas transmitting counterpart, it linked California with Hawaii and, through Hawaii, with Japan, and it provided ship-to-shore service across the Pacific. The Operating Building housed the receiving equipment and the staff who ran it.
Machine-generated summary. This summary was generated by a language model from the official nomination document and has not been reviewed line by line by an editor. It may contain errors. Check the source document before relying on any detail. Source: nomination document (PDF) · National Archives catalog entry. NRHP reference 89000819, listed July 24, 1989. Summary generated October 2026 (model claude-sonnet-5-5, prompt v1.0-2026-10-29, confidence high).
Key facts
| Address | 18500 CA 1, Marshall |
|---|---|
| County | Marin County |
| Listed | July 24, 1989 |
| Reference number | 89000819 |
| Resource type | Building |
| Period of significance | 1914-1931 |
| Architect / builder | J. C. White Engineering Company (the text also calls it the J.G. White Engineering Company of New York City) |
| Criteria |
|
| Areas of significance | Communications |
| Level of significance | National |
| Status (as stated in the nomination) | Used as a residence for the property's General Manager; the form says the property is being rehabilitated as a non-profit conference center. The veranda has been enclosed and interior walls reconfigured. |
| Acreage | 0.9 |
| Coordinates | 38.14407, -122.87843 (NPS GIS) |
What listing means for this property
For an income-producing building, listing (individually or as a contributing building in a district) is the gateway to the 20% federal rehabilitation tax credit on qualified rehabilitation costs, often stackable with state credits. Work claiming the credit must follow the Secretary of the Interior's Standards and be approved in advance.
Listing does not restrict a private owner acting without federal money or permits; where federal funding or licensing is involved, Section 106 review applies.
General information, not legal or tax advice. Rules change; confirm with your State Historic Preservation Office or a qualified adviser.
Sources and further reading
- National Park Service, National Register of Historic Places database (snapshot May 2026), reference 89000819.
- Nomination form (PDF, National Archives) — catalog entry
- Wikipedia article (used for cross-checking only; text not reproduced here)
- Wikidata Q14594560
- This listing as JSON
Last updated October 2026. Found an error? See the editorial policy for how to report it.