This route traces the "boundary stones", the original markers that established the nation's capital. That survey was laid out in a square, 10 miles on a side...such a cool route.
The Residence Act of July 16, 1790, as amended March 3, 1791, authorized President George Washington to select a 100-square-mile site for the national capital on the Potomac River between Alexandria, Virginia, and Williamsport, Maryland. President Washington selected the southernmost location within these limits so that the capital would include all of present-day Old Town Alexandria, then one of the busiest ports in the country. Acting on instructions from Secretary of State Thomas Jefferson, Major Andrew Ellicott began his initial observations for a rough survey of the ten-mile square on Friday, February 11, 1791.
Ellicott, a prominent professional surveyor, hired Benjamin Banneker, an astronomer and surveyor from Maryland, to make the astronomical observations and calculations necessary to establish the south corner of the square at Jones Point in Alexandria. According to legend, "Banneker fixed the position of the first stone by lying on his back to find the exact starting point for the survey ... and plotting six stars as they crossed his spot at a particular time of night." From there, Ellicott's team embarked on a forty-mile journey, surveying ten-mile lines first along the southwest line, then along The northwest line, next along the northeast line, and finally along the southeast line. The team completed this rough survey in April 1791.
More history here: https://www.boundarystones.org/
Submitter: Mike Wardian