From Citizendium, the Citizens' Compendium
Both the official residence and offices of the President of the United States are in the White House, at 1600 Pennsylvania Avenue N.W., Washington, D.C. 20001. The current building is a replacement for the first Presidential residence, partially burned by the British in the War of 1812, but the exterior stone walls are from the original building. Construction started in 1792, although it was not occupied until 1800 by President John Adams. While George Washington watched it built, he never lived in it.
1600 Pennsylvania Avenue is the address of the north face of the building, with a modest fenced lawn in front of it. The sweeping South Lawn, where large ceremonies are held and helicopters land, is actually the back of the building.
The White House proper has a West Wing and an East Wing; the Oval Office, or official office of the President, is in the West Wing. One of the mysteries of the District of Columbia, along with there being no "J Street" in the alphabetical grid in downtown Washington, is that there is no direct access between the White House and West Wing. Even the President must step into the open air to go between the buildings.
Immediately to the east is the United States Department of the Treasury building, which is joined by an underground tunnel, intended for shelter and emergency exit, in the Second World War. Immediately to the West is the Executive Office Building (EOB), now officially the Eisenhower Executive Office Building. Built in 1871, the EOB was long called the State-War-Navy Building, and, in the 19th century, contained most offices of the national security establishment. The New Executive Office Building is a nondescript modern high-rise building a block north on 17th Street; the original EOB was known as the Old EOB when the additional building was put into use; very few long-time Washington residents are aware of the "Eisenhower" designation.
Directly across Pennsylvania Avenue, or more properly across a pedestrian area blocked off after the Alfred Murragh Building bombing in Oklahoma City, is Lafayette Park. Next to Lafayette Park and directly across from the EOB is Blair House, the official guest house of the United States. During the Truman Administration, President Truman occupied Blair House while the White House was undergoing renovation; there was an assassination attempt by Puerto Rican nationalists who attempted to shoot their way into Blair House, killing one White House policeman. Only one Secret Service agent was between the surviving attacker at the President.
The Main Building
The West Wing
The Oval Office
The Situation Room
Contrary to popular opinion, the Situation Room is not a futuristic-looking command post. While it has extensive audiovisual equipment, including large displays, these are normally concealed behind wall panels. It looks like an executive conference room, although not nearly as ornate as many in industry.
There is a complex of staff offices supporting it 24 hours a day, and technical equipment is much more obvious there, operated as part of the mission of the White House Communications Agency.
The East Wing
The East Wing houses several staff offices, including those of the White House Social Secretary and the First Lady of the United States. It is also the public access point for public visitors to the White House and the Executive Residence; official visitors come to the entrance in the center of the north side of the main White House.
Eisenhower Executive Office Building (EOB)
Washingtonians tend to love or hate the external French Second Empire architecture of the EOB, which has complex ornamentation in granite, slate and cast iron. The interior is not open to the public, and is arguably more elegant and restrained inside; it has visually striking polished floor of large black and white diamond-shaped stones. Many of the entrances to outer offices, from the main corridor, have partial swinging doors, rather like those from a stereotyped Western saloon.
For many years, there was no official residence for the Vice President. Since it had been necessary to provide security and communications at each private residence, in 1974, Congress authorized a residence on the grounds of the Naval Observatory to be made the official residence of the incumbent Vice President of the United States, sending its occupant, the Chief of Naval Operations (CNO), to quarters at the Washington Navy Yard. Since the CNO had taken over what had long been the residence of the Superintendent of the Observatory, perhaps there was a certain justice.
Ceremonial and staff offices for the Vice President are in the Executive Office Building.