Bloomfield is a census-designated place in Sonoma County, California, U.S. It is located in a rural area about 11 miles (18 km) southwest of Santa Rosa, California at the junction of Bloomfield Road and Valley Ford Road. Americano Creek flows westward along the south edge of the town.
Bloomfield is located on part of Rancho Cañada de Pogolimi. In 1853, William Zellhardt built a house on the site of present-day Bloomfield, which attracted other immigrants and led to plans for a town in 1856. At one point in the late 1850s, Bloomfield was the second largest town in Sonoma County, and in 1877 it had four hotels and a population of 250. However, the town never recovered from being bypassed by the railroads, and its growth tapered off.