From Thomas Jefferson Encyclopedia
Dimensions: 27' 3" x 23' 8"; ceiling 18' 2"
Source: Palladio, with frieze from the Temple of Jupiter Tonans (Thunderer), from Desgodetz, Les Édifices Antiques de Rome
Color: Unpainted plaster, with a Thomas Jefferson-designed parquet floor of cherry and beech
Architectural features: Parquet floor, automatic double-doors (doors.qt)
Furnishings of Note: Artwork, with paintings hung in tiers. Jefferson's inventory, presumably made in 1809, lists for this room: "Portraits - 24; Paintings - 17; Medals - 10; Busts - 2; Miscellaneous - 4". Among the portraits were represented key figures in Jefferson's thinking and in American and world history. Jefferson displayed portraits of the "three greatest men that have ever lived" -- John Locke, Isaac Newton, and Francis Bacon, as well as discoverers such as Columbus and Magellan, and American notables such as Washington, Franklin, and Madison. Today, the room contains a bust of Jefferson by renowned sculpture Jean-Antoine Houdon.
The room held many chairs of varying designs, including several acquired in France and upholstered in crimson damask. The room contained several other chairs and sofas of varying styles, purchased elsewhere or made in the Monticello joinery. One of Jefferson's favorites, the campeachy chair, is discussed in the "A Delightful Recreation" section in "Jefferson."
Several tables for cards or other amusements were in the room, as well as musical instruments such as a harpsichord and piantoforte. Two gilded pier mirrors enhanced the light in the room, and the curtains on the windows were made from Jefferson's sketches