In 1791 and 1792, Andrew Ellicott and his surveying team placed 40 boundary stones around the perimeter of the District of Columbia, one at each mile of the original diamond shape. They laid the first stone, the south corner stone, at Jones Point on April 15, 1791, under the guidance of Benjamin Banneker.
From there, Ellicott’s team embarked on a 40-mile journey that took nearly two years. They created the boundary lines of the capital by clearing 20 feet of land on each side of the boundary and setting a uniquely marked stone at each mile interval. On each stone, the side facing the District of Columbia displayed the inscription “Jurisdiction of the United States” and a mile number. The opposite side said either “Virginia” or “Maryland,” as appropriate. The third and fourth sides displayed the year in which the stone was placed (1791 for the 14 Virginia stones and 1792 for the 26 Maryland stones) and the magnetic compass variance at that place.
The boundary stones are the oldest federal monuments. Although several have been moved or replaced, 38 boundary stones remain in or near their original locations.