History of Washington, D.C.
Georgetown was established in 1751 when the Maryland legislature purchased sixty acres of land for the town from George Gordon and George Beall at the price of £280, while Alexandria, Virginia was founded in 1749. Situated on the fall line, Georgetown was the farthest point upstream to which oceangoing boats could navigate the Potomac River. The strong flow of the Potomac kept a navigable channel clear year-round; and, the daily tidal lift of the Chesapeake Bay, raised the Potomac's elevation in its lower reach; such that fully laden ocean-going ships could navigate easily, all the way to the Bay. Gordon had constructed a tobacco inspection house along the Potomac in approximately 1745. Warehouses, wharves, and other buildings were added, and the settlement rapidly grew. The Old Stone House, located in Georgetown, was built in 1765 and is the oldest standing building in the District. It did not take long before Georgetown grew into a thriving port, facilitating trade and shipments of tobacco and other goods from colonial Maryland. With the economic and population growth of Georgetown came also the founding of Georgetown University in 1789, at its founding drawing students from as far away as the West Indies.
Georgetown University Astronomical Observatory
The Georgetown University Astronomical Observatory (also the Heyden Observatory and Francis J. Heyden Observatory) was founded in 1841 by Father James Curley of the Department of Physics at Georgetown College. Father Curley chose a site on the college grounds, planned the building, and supervised its construction to its completion in 1844. Costs were initially paid by Rev. Thomas Meredith Jenkins, S.J., and Rev. Charles H. Stonestreet, S.J., who were Georgetown professors at the time. The observatory was used in 1846 to determine the latitude and longitude of Washington, D.C., which Curley determined to be latitude 38°54′26N and longitude 5818.29 (west of Greenwich).