When engineer Pierre-Charles L'Enfant completed the original design for Washington in 1791, he wisely planned it for a population of 800,000 inhabitants, although at the time this was only about one quarter of the population of the entire United States. The District of Columbia forms a diamond shape within the V created by the Anacostia and Potomac rivers. At the center of the city are the Capitol , the National Mall , and the White House . Washingtonians refer to these quadrants often when giving directions or distinguishing neighborhoods from one another.
Numbered streets run north-south.
Avenues named for U.S. states run diagonally, often meeting at traffic circles and squares such as Dupont Circle. Northwest contains neighborhoods more likely to be of interest to visitors than the other quadrants. Most inhabitants are the affluent or moderately well-off who have chosen not to live in the suburbs. Georgetown attracts preppy partyers yet retains more than enough quaintness for the casual stroller. Georgetown University, oldest Roman Catholic and Jesuit university in the United States, is also a significant presence in the neighborhood.