“R” is for Robert Mills House [Columbia]. A National Historic Landmark, Columbia’s Robert Mills House is most noted for its association with the first American-trained architect and the first federal architect of the United States. Ironically, the building’s architect was best known as the architect of public works such as courthouses and jails—not private residences. Of further significance is the building’s role as the home of a regionally important religious institution—Columbia Theological Seminary-- and as an example of the grassroots historic preservation movement of the 1960s. Following a seven-year campaign by the Historic Columbia Foundation for its restoration, the building opened to the public in 1967, as a historic house museum showcasing the neoclassical architecture and decorative arts of the early 19th century. The Robert Mills House exemplifies early 19th century classical revival design.