Winnsboro Mills is an unincorporated community and census-designated place (CDP) in Fairfield County, South Carolina, United States.

It is part of the Columbia, South Carolina Metropolitan Statistical Area.

Winnsboro Mills is located southeast of the center of Fairfield County at 34°21′24″N 81°4′58″W / 34.35667°N 81.08278°W / 34.35667; -81.08278 (34.356734, -81.082834).

According to the United States Census Bureau, the CDP has a total area of 2.6 square miles (6.8 km2), all of it land.

29.5% of all households were made up of individuals, and 12.8% had someone living alone who was 65 years of age or older.