the borders of the Territory of Columbia with Virginia and Maryland during 1791 and 1792. The survey team enclosed within a square an area containing the full that the Residence Act had authorized. Each side of the square was long. The axes between the corners of the square ran north–south and east–west. The center of the square is within the grounds of the Organization of American States headquarters west of the Ellipse. The survey team placed forty sandstone boundary markers at or near every mile point along the sides of the square (see: Boundary markers of the original District of Columbia). Thirty-six of these markers still remain. The south cornerstone is at Jones Point. The west cornerstone is at the west corner of Arlington County, Virginia. The north cornerstone is south of East-West Highway near Silver Spring, Maryland, west of 16th Street. The east cornerstone is east of the intersection of Southern Avenue and Eastern Avenue. On January 1, 1793, Andrew Ellicott submitted to the commissioners a report that stated that the boundary survey had been completed and that all of the boundary marker stones had been set in place. Ellicott's report described the marker stones and contained a map that showed the boundaries and topographical features of the Territory of Columbia. The map identified the locations within the Territory of the planned City of Washington and its major streets and the location of each boundary marker stone. Plan of the City of Washington In early 1791, President Washington appointed Pierre (Peter) Charles L'Enfant to devise a plan for the new city in an area of land at the center of the federal territory that lay between the northeast shore of the Potomac River and the northwest shore of the Potomac's Eastern Branch. L'Enfant then designed in his "Plan of the city intended for the permanent seat of the government of the United States ... " the city's first layout, a grid centered on the United States Capitol, which would stand at the top of a hill (Jenkins Hill) on a longitude designated as 0,0°. The grid filled an area bounded by the Potomac River, the Eastern Branch (now named the Anacostia River), the base of an escarpment at the Atlantic Seaboard Fall Line along which a street (initially Boundary Street, now Florida Avenue) would later travel, and Rock Creek. North–south, and east–west streets formed the grid. Wider diagonal "grand