Gianella Bridge
Also known as: Sacramento River Bridge at Hamilton City
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Why it's listed
Carrying State Highway 32 over the Sacramento River at Hamilton City, this steel bridge links Glenn and Butte Counties. It has two Pratt truss approach spans of 133 feet each and a 311-foot swing span, all resting on mass concrete piers. Built between 1908 and 1910 by Cotton Brothers of Oakland and opened in early 1911 after delays, it was designed by John B. Leonard, a leading state bridge engineer who usually worked in reinforced concrete. The counties chose steel because it cost less at first. The crossing location, favored by Butte County farmer Vincenzo Gianella, served the sugar beet refinery at Hamilton City, and the two rival counties cooperated to build it. It is the oldest swing span movable bridge on the State highway system. The deck was replaced in 1937 and again in 1954, and the swing span has stayed closed to river traffic since a 1972 agreement with the Coast Guard.
Significance in brief: It is the oldest swing span movable bridge on the State highway system. Its construction marked a rare instance of cooperation between two rival counties. It is also the only known steel bridge by engineer John B. Leonard, and it supported the sugar beet industry around Hamilton City.
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 82004614, listed July 8, 1982. Summary generated October 2026 (model claude-sonnet-5-5, prompt v1.0-2026-10-29, confidence medium).
Key facts
| Address | CA 32, Hamilton City |
|---|---|
| County | Glenn County |
| Listed | July 8, 1982 |
| Reference number | 82004614 |
| Resource type | Structure |
| Period of significance | 1908-1911 |
| Architect / builder | Cotton Brothers & Co., Contractors / John B. Leonard, C.E. |
| Areas of significance | Engineering, Transportation |
| Level of significance | Local |
| Status (as stated in the nomination) | Altered but in good condition; the swing span has not been opened since 1972, though it must be restorable to opening within six months of Coast Guard notice. |
| Acreage | 0.9 |
| Coordinates | 39.75103, -121.99726 (NPS GIS) |
What listing means for this property
For a publicly owned building or structure, listing mainly matters when federal funds, permits or licences are involved: projects then go through Section 106 review so effects on the property are considered. Listing also strengthens applications for preservation grants and, for leased income-producing uses, can enable the federal rehabilitation tax credit.
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 82004614.
- Nomination form (PDF, National Archives) — catalog entry
- Wikipedia article (used for cross-checking only; text not reproduced here)
- Wikidata Q14682015
- This listing as JSON
Last updated October 2026. Found an error? See the editorial policy for how to report it.