Smith Mills is a census-designated place (CDP) in the town of Dartmouth in Bristol County, Massachusetts, United States.

[3] According to the United States Census Bureau, the CDP has a total area of 12.4 km2 (4.8 mi2), of which 12.3 km2 (4.7 mi2) is land and 0.2 km2 (0.1 mi2) (1.46%) is water.

As of the census[5] of 2000, there were 4,432 people, 1,861 households, and 1,269 families residing in the CDP.

The racial makeup of the CDP was 95.62% White, 0.27% African American, 0.27% Native American, 1.06% Asian, 0.05% Pacific Islander, 1.31% from other races, and 1.42% from two or more races.

27.4% of all households were made up of individuals, and 16.7% had someone living alone who was 65 years of age or older.