Duncans Mills (or Duncan's Mills) is an unincorporated community located in Sonoma County, California. Duncans Mills is located at 38°27′14″N 123°3′18″W on the Russian River about 4 mi (6 km) from the Pacific Ocean. It straddlesState Route 116.
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.