Final answer:
Benjamin Banneker aided in moving the U.S. capital by surveying the area along the Potomac River, leading to the establishment of the District of Columbia.
Step-by-step explanation:
Benjamin Banneker helped President Washington move the nation's capital by surveying the territory for the new federal city, the District of Columbia.
Banneker, a self-taught free African American man with knowledge in astronomy and mathematics, was part of the team tasked with surveying the land designated by the Residence Act of 1791, which identified an area along the Potomac River for the new capital. He worked alongside Major Andrew Ellicott to map out the area, which was officially named the District of Columbia, resulting from the Compromise of 1790 where Alexander Hamilton agreed to a southern capital in exchange for support for his financial policies.