Blair House, also known as The President's Guest House, is an official residence in Washington, D.C., the capital of the United States. The President's Guest House has been called "the world's most exclusive hotel" because it is primarily used as a state guest house to host visiting dignitaries and other guests of the president. Parts of the historic co…Blair House, also known as The President's Guest House, is an official residence in Washington, D.C., the capital of the United States. The President's Guest House has been called "the world's most exclusive hotel" because it is primarily used as a state guest house to host visiting dignitaries and other guests of the president. Parts of the historic complex have been used for an official residence since the 1940s.