[3][4] The Historic Columbia Foundation owns and operates the home, which has been furnished with decorative arts of the early 19th century, including American Federal, English Regency, and French Empire pieces.

The Robert Mills House is located in a parklike 4-acre (1.6 ha) parcel that occupies an entire city block in central Columbia.

It is a two-story masonry structure, built out of brick set on a high basement with arcaded walls.

Its main facade faces north, with a Classical projecting portico that has four Ionic columns supporting a gabled pediment.

The hall has curved ends, as do the matching parlors, providing an illusion of increased space.