THOMAS JEFFERSON'S contributions to American architecture are recognized by anyone with even a passing interest in architectural history. His ideas on the planning of the city of Washington, preferring as he did a simple grid layout to L'Enfant's involved baroque scheme, are perhaps less familiar but certainly not undocumented. Virtually unknown, however, are Jefferson's later theories of city planning and their application during and after his presidency to at least two communities. Jefferson as a city planner certainly achieved less renown than in his more familiar roles as statesman, philosopher, or architect. Nevertheless, his ideas of how to plan cities rank with the other products of his astonishingly fertile mind in originality, logic, and interest. We know from his activities in connection with the early planning of Washington that Jefferson was an undeviating advocate of rectangular layouts. At first, late in 1790, with a site at the mouth of the Anacostia in mind and later, in March of the following year with the site shifted northward, he submitted rough sketch plans of gridiron towns to the President. And in a letter to Washington mentioning that he had supplied L'Enfant with plans of Frankfurt, Karlsruhe, Paris, Orleans, Milan, Amsterdam, and half a dozen other cities, he added the comment that 'they are none of them however comparable to the old Babylon, revived in Philadelphia . . .' It is significant also that in the mass of correspondence, notes, and memoranda written by Jefferson on the city of Washington, apparently not one comments favorably on the radial plan devised by L'Enfant. In all this he was consistent with his earlier support of the rectangular system of surveys in the public domain established by the Land Ordinance of 1785 and his scheme for the creation of new states with rectangular boundaries in the Northwest Territory. We see Jefferson, then, a faithful adherent to the grid or checkerboard plan, although he did not allow this strong preference to affect his relationship with L'Enfant. It was, of course, L'Enfant's philosophy of baroque planning that prevailed in the planning of the national capital. Jefferson's direct contribution to city planning in America was yet to be made.