AbstractThe influence of Versailles on L’Enfant’s 1791 plan for the city of Washington, DC, is well known. Less well known are the surprising similarities between Washington and the forma urbis of the Royal Site of Aranjuez in Spain. For example, the cities share the same diagram of two large, rectangular spaces arranged in an L shape, at the extremes of which are located, analogously, the most emblematic buildings: The Capitol and the White House in one instance, and the Royal Palace and the Church of San Antonio in the other. There are also connections between some of the diagonal avenues; between the Plaza de las Doce Calles in Aranjuez and the 12 avenues radiating from the Capitol; and between the trident of Parterre Garden in Aranjuez and the trident formed in L’Enfant’s plan by Pennsylvania Avenue NW, Maryland Avenue SW, and Avenue H. Based on these facts, this paper investigates parallels that have hitherto been ignored. It is not possible to conclude, based on the currently available information, that L’Enfant was familiar with the plan for Aranjuez, which was sent in 1775 to the main European courts, where it is conserved in their libraries. A copy of the plan is also the Library of Congress in Washington, DC. There is evidence that L’Enfant’s father, and possibly he himself, saw it in Paris at the Académie Royale de Peinture et de Sculpture, at which L’Enfant was studying before his departure for the United States. He may also have seen it during a visit to Paris in 1783, when the creation of a new capital had been proposed and he was a candidate to plan it because of his relationship with George Washington. Similarly, Thomas Jefferson may have seen the plan during his time as ambassador in Paris, given that, in his own sketch for the new capital, he situated the White House and the Capitol in the same compositional relationship as L’Enfant did later. These similarities may also simply be coincidence; in any case, they invite questions.