Sonoma Plaza (Boundary Increase)
Also known as: See Also:Sonoma Plaza
Why it's listed
Sonoma Plaza and its surrounding blocks form a historic district in Sonoma, California, with a large, flat, tree-filled plaza at the center and a grid of streets extending outward. Commercial buildings of one to four stories face the plaza, while the side streets are mostly one-story houses. Buildings date from the 1830s to the 1930s and include adobes, Italianate storefronts, Queen Anne and Eastlake houses, bungalows, and Mission Revival structures. The plaza was once a Mexican-era parade ground and later gained Bear Flag monuments, the 1906 City Hall, a 1910 Carnegie Library, a duck pond and extensive plantings. The district also includes the Mission San Francisco Solano site, the Casa Grande site and the Swiss and Toscano hotels. The period of significance runs from 1835 to 1944. Few high-rise or modern intrusions exist, and most changes are low-rise construction or replaced windows. The district keeps the character of a small country town center, and the boundary increase adds areas along Broadway and East Napa Street.
Significance in brief: The district keeps the look and character of a small country town center, with a Mexican-era plaza, mission site and adobes alongside later commercial and residential buildings. It records the town's development from the Mexican period and the 1846 Bear Flag events through early 20th century civic improvements. Integrity is described as very high, with few intrusions.
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 92000293, listed May 6, 1992. Summary generated October 2026 (model claude-sonnet-5-5, prompt v1.0-2026-10-29, confidence medium).
Key facts
| Address | Area S and E of town plaza, along Broadway and the N side of E. Napa St., Sonoma |
|---|---|
| County | Sonoma County |
| Listed | May 6, 1992 |
| Reference number | 92000293 |
| Resource type | District |
| Period of significance | 1835-1944 |
| Architectural style | Mid-19th Century California Monterey Colonial; Late Victorian (Queen Anne, Eastlake); Beaux Arts, Mission and Spanish Colonial Revival; Bungalow |
| Areas of significance | Community Planning and Development, Commerce, Architecture |
| Level of significance | State, Local |
| Status (as stated in the nomination) | Described as retaining very high integrity with minor change; several buildings are in commercial, civic and residential use, and the 1891 Mission Hardware building was lost to fire in 1990. |
| Acreage | 2 |
| Coordinates | 38.28592, -122.46083 (NPS GIS) |
What listing means for this property
This is a historic district. Buildings within its boundary are either contributing (they add to the district's significance) or non-contributing. Owners of contributing income-producing buildings can claim the 20% federal rehabilitation tax credit; homeowners should look at state credits. National Register districts impose no design review by themselves; a local historic district ordinance, if one exists, does (the difference explained).
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 92000293.
- Nomination form (PDF, National Archives) — catalog entry
- Wikipedia article (used for cross-checking only; text not reproduced here)
- Wikidata Q7562188
- This listing as JSON
Last updated October 2026. Found an error? See the editorial policy for how to report it.