Washington’s climate is hot and humid in the summer and cold and damp in the winter. The average daily temperature range is -3° C (27° F) to 8° C (46° F) in January and 22° C (72° F) to 31° C (88° F) in July. The city averages 98 cm (39 in) of precipitation per year.
II WASHINGTON AND ITS METROPOLITAN AREA A The Outline of the City Designated to serve as the permanent seat of the federal government beginning in 1800, the District of Columbia was named for Christopher Columbus. It was created from land ceded by the states of Virginia and Maryland, and it incorporated the existing seaport towns of Alexandria, Virginia, and Georgetown, Maryland. The district was originally 259 sq km (100 sq mi), or 10 miles square, as established under the Residence Act of 1790. The central town site was laid out by French architect Pierre Charles L’Enfant in 1791. The remaining land was an open area stretching north to the border with Maryland. It was designated as Washington County. In 1846 Congress returned that portion of the federal district that had originally been ceded by Virginia.
In 1871 the cities of Washington and Georgetown were consolidated with Washington County to become Washington, D.C., making the city, the county, and the federal district one and the same. Washington, D.C. has a total area of 176 sq km (68 sq mi), and the Washington metropolitan region—which in addition to Washington, D.C., contains 24 counties in the surrounding states of Maryland, Virginia, and West Virginia—has a total area of 17,920 sq km (6920 sq mi).
In his plan for the city of Washington, L’Enfant attempted to represent symbolically the new United States and its republican government. He gave prominence to each of what were then the primary elements of government—the executive and the legislative branches. He also featured the states in giving their names to broad diagonal avenues. These he arranged both according to geography and to each state’s prominence in the nation-building process. Massachusetts, Virginia, and especially Pennsylvania, with its associations both with the Declaration of Independence and the signing of the Constitution, gained the most prominence. Avenues named after other states with prominent roles in ratifying the Constitution, notably Delaware and New Jersey, intersected at the Capitol. Also, L’Enfant hoped that the intersection of diagonal avenues with the city’s straight grid of numbered and lettered streets would provide squares where each state would locate facilities, thereby giving them the same symbolic importance in the capital city that they held in the federal system.
B Patterns of Settlement and Development Initially Washington was slow to develop the dense pattern of settlement characteristic of cities. By the 20th century, however, Washington had filled its open spaces and dominated the surrounding area, which remained largely rural. This pattern changed after World War II (1939-1945), as the city lost population to the suburbs of Virginia and Maryland. While the federal presence remained concentrated in Washington, it also expanded considerably to the suburbs. At the same time, new private business—the fastest-growing source of regional employment—concentrated almost exclusively in the areas outside the city.
While the metropolitan area expanded outward, it did not do so randomly. Growth tended to follow the location of federal facilities outside the city and the development of major transportation routes. During World War II, the construction of the Pentagon as the headquarters of the Department of Defense spurred development nearby on the Virginia side of the Potomac River. Growth was also stimulated by other key facilities, notably the Central Intelligence Agency (CIA) in Langley, Virginia; and the Atomic Energy Commission (AEC), the National Bureau of Standards (now the National Institute of Science and Technology), and the National Institutes of Health (NIH) , all in Maryland.
C Public Buildings Washington is home to many famous and interesting public buildings and monuments. Many of these are associated with the federal government. The Capitol of the United States is located on a hill rising 27 meters (88 feet) above the Potomac and consists of two wings that branch from a central rotunda. The north wing is occupied by the Senate, and the south wing by the House of Representatives. The rotunda is crowned by an immense dome, topped with a statue of a woman representing Freedom. East of the Capitol is the Supreme Court Building, with its portico modeled after a Greek temple. North of the Capitol, at the end of Delaware Avenue, stands massive Union Station, now a retail center as well as a train station that has long been a hub of the city.
From the Capitol, Pennsylvania Avenue runs slightly northwest and Constitution Avenue runs directly west. Between 6th and 15th streets NW the two avenues form an area known as the Federal Triangle. Within this triangle are concentrated a number of government buildings, including those of the Federal Trade Commission (FTC), the Internal Revenue Service (IRS), and the departments of Justice and Commerce. Also in the triangle is the National Archives Building, which contains the original drafts of the Declaration of Independence, the Constitution of the United States, and the Bill of Rights.
Just north of the triangle, on Tenth Street NW, is the J. Edgar Hoover Building, the headquarters of the Federal Bureau of Investigation (FBI). On the block north of the Hoover building, also on Tenth Street, is Ford's Theatre, where President Abraham Lincoln was shot in 1865, and across the street is the Petersen House, where he died. Together they make up Ford’s Theatre National Historic Site.
Northwest of the triangle, at 16th Street and Pennsylvania Avenue, is the oldest federal building in Washington, the White House, official residence of the U.S. president. The mansion's foundations were laid in 1792, and every president except George Washington has occupied it. Tours are conducted daily through the most-famous ground-floor and first-floor rooms, such as the East Room, the Blue Room, and the State Dining Room.
Flanking the White House are the Treasury Department Building to the east and the Executive Office Building to the west. Across the street is Blair House, the official guest house for visiting heads of state and other dignitaries. Blair House, built in 1824, served as a temporary executive mansion for President Harry S. Truman and his family from 1948 to 1952, while the interior of the White House was being extensively reconstructed.
North of the White House is Lafayette Square, with a statue of General Andrew Jackson made from a melted-down cannon captured by Jackson during the War of 1812. West of the White House, at New York Avenue and 18th Street NW, is one of Washington's oldest landmarks, the Octagon. Completed in 1801, the Octagon houses a museum dedicated to architecture and the early history of Washington, and is also home to the American Architectural Foundation. It was one of the first residential structures built according to L’Enfant’s plan. During the War of 1812, British troops set fire to the White House, destroying its interior. President James Madison and his family lived in the Octagon while the White House was being rebuilt.
South of the Federal Triangle is the Mall, a narrow park stretching roughly 1.6 km (1 mi) from the Capitol to the Washington Monument. Although the Mall officially ends at 14th Street, landscaped greenery extends to the Potomac. The Washington Monument, whose marble shaft dominates the skyline, stands 169 meters (555 feet) high near the center of this parkland. The interior of the monument is hollow, and visitors may either climb its 898 steps or ride its elevator 150 meters (500 feet) for a magnificent view. A height restriction law enacted by Congress in 1899 ensures that no private structure in Washington, D.C., will extend higher than the monument or the Capitol.
Beyond the monument in West Potomac Park, still in a straight line from the Capitol, is the massive Lincoln Memorial. This monument’s 36 columns represent the 36 states in the Union at the time of Lincoln's death in 1865.