of the site. However, President George Washington wished to include the town of Alexandria, Virginia, within the federal district. To accomplish this, the boundaries of the federal district would need to encompass an area on the Potomac that was downstream of the mouth of the Eastern Branch. The U.S. Congress amended the Residence Act in 1791 to permit Alexandria's inclusion in the federal district. However, some members of Congress had recognized that President George Washington, and his family, owned property in and near Alexandria, which was just seven miles (11 km) upstream from Mount Vernon, Washington's home and plantation. The amendment, therefore, contained a provision that prohibited the "erection of the public buildings otherwise than on the Maryland side of the river Potomac". The final site was just below the fall line on the Potomac, the furthest inland point navigable by boats (see: Atlantic Seaboard fall line). It included the ports of Georgetown and Alexandria. The process of establishing the federal district, however, faced other challenges in the form of strong objections from landowners such as David Burns who owned a large, tract of land in the heart of the district. On March 30, 1791, Burns and eighteen other key landowners relented and signed an agreement with Washington, where they would be compensated for any land taken for public use, half of the remaining land would be distributed among the proprietors, and the other half to the public. Pursuant to the Residence Act, President Washington appointed three commissioners (Thomas Johnson, Daniel Carroll, and David Stuart) in 1791 to supervise the planning, design and acquisition of property in the federal district and capital city. In September 1791, using the toponym Columbia and the name of the president, the three commissioners agreed to name the federal district as the Territory of Columbia, and the federal city as the City of Washington. On March 30, 1791, Washington issued a presidential proclamation that established "Jones's point, the upper cape of Hunting Creek in Virginia" as the starting point for the federal district's boundary survey. The proclamation also described the method by which the survey should determine the district's boundaries. Working under the general supervision of the three commissioners and at the direction of President Washington, Major Andrew Ellicott, assisted by his brothers Benjamin and Joseph Ellicott, Isaac Roberdeau, Isaac Briggs, George Fenwick, and, initially, an African American astronomer, Benjamin Banneker, then proceeded to survey