Oak Ridge began as the plantation of Margaret Cabell and her husband, Robert Rives, a tobacco planter, merchant, and owner of several stores along the James River. The Riveses built the original double-pile, central-passage section of the main house. But today's Oak Ridge is primarily the creation of Thomas Fortune Ryan, who bought the farm one hundred years later. Born in Lovingston, Ryan became one of the wealthiest financiers in America and a munificent Catholic philanthropist. By 1908, he had converted the old Federal house into an enormous Classical Revival house perhaps designed by Carrère and Hastings, who designed the Ryan mausoleum at Oak Ridge, or by Lynchburg's John Minor Botts Lewis of Lewis and Burnham, architect of the estate's many Arts and Crafts outbuildings. The five-bay Federal section of the two-story brick house is flanked by two-story wings with one-story porches. In the center of the facade is a pedimented portico carried on full-height paired Ionic columns and a long, low balustrade around the platform porch. The garden side of the house has another favorite portico of the period, a centered, flat-roofed semi-circle with full-height columns. The garden is an elaborate, terraced Italian design edged in part by a glorious rotunda greenhouse with long, angled wings.
Relieving the stiff formality of the house are the picturesque outbuildings peppered around the forty-eight-hundred-acre grounds. Designed by Lewis in the early twentieth century, they are informal Arts and Crafts essays in rubble, with picturesque roof shapes and external stairs and loggias. The springhouse/ teahouse accommodates a first-floor dairy with troughs edging the tile walls, above which is a teahouse with a loggia where ladies could relax and look out onto Oak Ridge's nine-hole golf course. Other outbuildings include a kitchen, chauffeur's house, carriage house, farm manager's house, tenant houses, barns, corncrib, and piggery. The estate is now used for events.