Archaeology Sheds New Light on Jefferson's "Air Closets" and the Privy Tunnel

Archaeologists recently completed excavations of a segment of a 150-foot-long stone tunnel running beneath Monticello's East Lawn (Figure 1) . The tunnel ventilated three indoor privies that Thomas Jefferson installed in the mansion as part of an ambitious campaign launched in 1796 to rebuild his house. It was an unusual decision. We know of no other examples in Colonial North America or the Early Republic. While even the wealthiest planters of his era, including George Washington at Mount Vernon, built their privies outside, Jefferson brought his indoors.

Figure 1: Monticello's archaeologists and the excavated segment of the privy tunnel.

Our excavation has prompted us to take a closer look at the documentary and material evidence to understand how Jefferson's indoor privies and the privy tunnel worked, who maintained them, and why he might have designed them and ordered their construction. For more on how the tunnel was engineered by its builders to take advantage of local geology, see our earlier blog post (Neiman 2025).

First, we consider evidence for Jefferson's design of the indoor privies and the tunnel. The privies were located in three adjacent, vertical brick shafts that were built during the rebuilding campaign of the 1790s. The first version of the mansion lacked indoor privies. The three shafts were located between the eastern wall of Jefferson's bedroom and the parallel western wall of the southern side passage  (Mesick Cohen and Wait Architects 1991[1993]:58, 65). Two of the privies were located on the ground floor. One was accessed from Jefferson's bedroom and the second from southern side passage from the sitting room used by his daughter Martha. The third privy was located off the southern side passage on the second floor.

Figure 2: Ground-floor plan of the second version of Monticello mansion.

The privy tunnel was an important aspect of Jefferson's design. Its open southern end emerged from the south-facing slope that separate the level East Lawn from Mulberry Row. From there it traveled 150 feet north, buried beneath the East Lawn. Once the tunnel intersected the house, it continued as a brick barrel vault for another 25 feet, running under the basement floor. The tunnel then intersected the bottoms of the three brick shafts that served the privies above. The shafts traveled up through the basement and the three stories of the house, terminating in a skylight in the roof. We suspect that Jefferson designed this arrangement in hopes that air would be drawn into the tunnel and travel up the shafts, taking odors with it. Jefferson referred to the indoor privies as "air closets," a neologism that we think alludes to this aspect of the design. Just how well the arrangement worked is not clear.

Just what did the privies look like and how were they maintained? Much of the physical evidence has been destroyed or is currently inaccessible. In the 1950s Monticello's curators installed HVAC conduits in two of the privy shafts. These are still in use today. About the same time, architect Milton Grigg restored the privy adjacent to Jefferson's bedroom, leaving behind no traces or record of the original evidence. However, we can glean some important insights from Jefferson's letters.

In a letter and an accompanying drawing from 1794, several years before construction began, Jefferson laid out his design for the privies. It featured a plank seat and floor in front of it, suspended above an open-air shaft. He wrote "the floors & seats to be grooved into a string board thus the string board forked at bottom, & leaning against back to as to need no sleepers across the flues." Jefferson used the "string board" or ledger, set on a diagonal, to ensure the open shaft below the seat was unobstructed (Figure 3). The design implies that Jefferson's original intent was for waste to drop to the bottom of the shaft in the basement.

Figure 3: Jefferson's design for the privy floor and seat comprised of planks fitted into grooves in a diagonal ledger board.

Further clues come from an 1802 letter, when the rebuilding campaign was well underway. Jefferson asked joiner James Oldham to prioritize finishing the carpentry in the second and third air closets. His reasoning was simple: "…because it will be very disagreeable working in them after even one of them begins to be in use" (Jefferson 1802). This makes sense if the waste from each adjacent shaft ended up in a single receptacle where it was allowed to accumulate.

Accumulating waste had to be removed. Starting in 1806, Jefferson recorded regular payments to enslaved people over two decades to clean the "sewers." There are roughly 130 payments between 1806 and 1826 (e.g., Bear and Stanton 1997:1181, 1305, and 1355). The same people reappear throughout the accounts and include Ben, Phil, Ned, Nace, and Moses. Jefferson paid 1 dollar for one month's work, an amount that was roughly the daily wage for an unskilled free laborer. The frequency of payments was typically monthly. However, waste removal may have taken place more frequently.

Just how this unpleasant task was accomplished remains unclear. We do not know how the receptacle at the bottom of the shafts that required cleaning was accessed. Any evidence, if it survives, is obscured under the modern basement floor and the HVAC conduit that fills the brick shafts.

Jefferson's descriptions of his plan for the tunnel indicate it was an essential part of the overall design from the start. In his 1794 remodeling notebook, Jefferson calculated the length (40 yards), breadth (1½ yards), depth (2 yards), and total cubic yards (120) of the excavated "sink" (Jefferson 1794). In another document from 1794, Jefferson detailed how the tunnel, which he called a "sink conduit," was to intersect the house:

"Sink conduit is to be 2-6½ wide. but adjacent to the chamber it will be only 2-2½ because of the thickening of the wall which projects outwardly at the angle of commencement 4. I. which allows for the pavement 3. I. arch 9 I. clear height 3.ft.=4ft. to which must be added the pavement of the sink" (Jefferson 1794-1797)

In that same document he recorded that the slope of the tunnel was "to descend 1. in 40. or 3 I. in 10 f." Finally, he noted that "the S.W. face internal to coincide with inner face of S.W. pier of middle arch of piazza then to go South Eastwardly parallel with axis of house."

Five years later at the end of December 1799, Jefferson urged Monticello overseer Richard Richardson to begin construction of the tunnel: "Do the wall of the sink. It is to be 3 f. wide and high in the clear, & to descend 3 I. in 10 feet" (Jefferson 1799). His measurements matched his earlier calculations. Later in the same memorandum, he asked that Richardson coordinate workers to "Haul slatestone from the quarry for the sink and for the covered way, kitchen, & office" (Jefferson 1799). However, our excavations revealed that the floor of the privy tunnel was never paved, an omission that makes sense since a stone floor was unnecessary for the tunnel to do its job.

During our excavations, we carefully recorded the stratigraphic layers representing the original mountaintop ground surface and the episodes of digging and deposition that created the artificial topography of the East Lawn that we see today. We learned that the 150-foot-long stone tunnel was carefully constructed in a trench dug through these earlier layers. The trench was from 3-to-6-feet deep and 6-feet wide.

How might we understand Jefferson's willingness to spend so much effort on the construction of his "air closets" and tunnel? We begin by emphasizing that Jefferson's design was unique. We know of no other examples of interior privies or the air shaft and tunnel arrangement from the time. In the early Chesapeake, most plantation-owning elites used chamber pots or simply stepped outside to relieve themselves. Sherds of ceramic chamber pots litter archaeological sites from the 17th and early 18th centuries, while privies are extremely rare. However, by the middle of the 18th century, as standards changed and levels of wealth among elites increased, outdoor privies became more common. They were an amenity that could only be afforded by the wealthiest planters. Their costly masonry construction and fine exterior and interior architectural finishes exceeded practical requirements for a functioning privy. They cannot be explained solely by the builder's desire for convenience. They had a social function as hard-to-fake signals of elite status. Washington's Mount Vernon and William Byrd III's Westover in Virginia and Charles Drayton's Drayton Hall in South Carolina offer examples (Chappell 2013:44-45).