Los Alamos Ranch House
Also known as: Rancho Los Alamos (de la Guerra); Los Alamos Rancho
Why it's listed
Rancho Los Alamos, in Santa Barbara County, California, centers on a long one-story adobe ranch house about three miles north of the town of Los Alamos. The 48,803-acre rancho was granted to Jose Antonio de la Guerra y Carrillo by Governor Juan Alvarado in 1839, and Indians from a rancheria on the estate built the house. It was fitted to the hillside and shows some American influence in its plank floors, board ceilings, paneled doors and six-paned window sashes. In the era of Mexican ranchos, it was a favorite overnight stop for travelers on El Camino Real between Santa Barbara and Monterey. The house has been carefully restored, with central heating, electricity and some picture windows added, though its original appearance is little changed. Many original furnishings remain, and the ranch setting is intact. It was recognized as probably the finest surviving Mexican-period adobe ranch house, and it still serves as a residence and working ranch.
Significance in brief: The form calls it probably the finest surviving example of the Mexican-period traditional one-story adobe ranch house. It sits in an unaltered rural setting that gives a clear picture of ranch life in Mexican California. It was also a favorite overnight stop for travelers on El Camino Real between Santa Barbara and Monterey.
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 70000148, listed April 15, 1970. Summary generated October 2026 (model claude-sonnet-5-5, prompt v1.0-2026-10-29, confidence medium).
Key facts
| Address | 3 mi. W of Los Alamos on old U.S. 101, Los Alamos |
|---|---|
| County | Santa Barbara County |
| Listed | April 15, 1970 |
| Reference number | 70000148 |
| Resource type | Building |
| Architect / builder | Built by Indians from a rancheria on the estate, for Jose Antonio de la Guerra y Carrillo |
| Architectural style | Mexican period one-story adobe ranchhouse, with some American influence |
| Areas of significance | Exploration/Settlement, Architecture |
| Level of significance | National |
| National Historic Landmark | Yes, designated April 15, 1970 |
| Status (as stated in the nomination) | Described as carefully restored and largely unaltered in a preserved ranch setting, with central heating, electricity and some picture windows added. Present use is residence and ranch. |
| Acreage | 800 |
| Coordinates | 34.75489, -120.33676 (NPS GIS) |
What listing means for this property
National Register listing is honorary for a privately owned home: it does not by itself restrict what an owner may do with their own money, and it does not require public access. Restrictions come from local landmark or historic-district ordinances, which are separate (how they differ).
Owner-occupied houses are not eligible for the 20% federal rehabilitation tax credit, which applies to income-producing buildings, but many states offer credits for homeowners. Listing also opens the door to preservation easements and to buying a plaque. Start with what listing means for homeowners, renovating a listed house and selling one.
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 70000148.
- Nomination form (PDF, National Archives) — catalog entry
- Wikipedia article (used for cross-checking only; text not reproduced here)
- Wikidata Q6681872
- This listing as JSON
Last updated October 2026. Found an error? See the editorial policy for how to report it.