| Official Name: | Duncans Mills, California |
| Other Name: | Duncanville |
| Pushpin Map: | California |
| Pushpin Label Position: | right |
| Pushpin Map Caption: | Location within the state of California |
| Subdivision Name: | United States |
| Population As Of: | 2000 |
| Population Total: | 85 |
| Utc Offset: | -8 |
| Timezone Dst: | PDT |
| Utc Offset Dst: | -7 |
| Coordinates: | 38.4539°N -123.055°W |
| Elevation Ft: | 35 |
| Postal Code: | 95430 |
| Blank Info: | 06-20130 |
| Blank1 Name: | GNIS feature ID |
| Blank1 Info: | 222722 |
Duncans Mills (or Duncan's Mills) is an unincorporated community located in Sonoma County, California.
Duncans Mills was once part of the Rancho Muniz Mexican land grant.
In 1877, Alexander Duncan established a sawmill in what is today Duncans Mills. The mills sent lumber to the growing city of San Francisco.
The town was founded in the 1870s. It featured two hotels, a general store, a saloon, a meat market, blacksmith, livery stable, and a notion shop.
Starting in the 1870s, the narrow-gauge North Pacific Coast Railroad ran through Duncans Mills on its way from Cazadero, California, to Sausalito. After being sold several times, the railroad ceased operation in the 1930s. The town slowly faded, until a 1976 restoration project, associated with the celebration of the U.S. Bicentennial, brought about a period of building restoration and business re-vitalization.
Today, Duncans Mills resembles the way it was originally built. It has an authentic North Pacific Coast Railroad Depot and several original cars from the old railroad line. A California State Park Sector Office is located in a building constructed to look like an original fixture of the town, but was actually part of the 1976 revitalization. The Blue Heron Restaurant has served as the destination entertainment center of the town for decades.
Duncans Mills is located on the Russian River about 40NaN0 from the Pacific Ocean. It straddles State Route 116.
The record high was 113°F on July 14, 1972, and the record low was 14°F on December 23, 1990.
According to the 2000 census, about 175 people live in Duncans Mills. There are around 42 family households and 31 non-family households. Each household has an average of 2–3 people. In Duncans Mills, there are 129 houses; 56 of them are vacant and 52 of them are of seasonal, recreational, or occasional use.