Number One Observatory Circle

Number One Observatory Circle is the official residence of the vice president of the United States. Located on the grounds of the U.S. Naval Observatory in Washington, D.C., it is sometimes informally referred to simply as "the Naval Observatory". The house was built in 1893 for the observatory's superintendent. The U.S. Navy's chief of naval operations (CNO) liked the house so much that in 1923 he took over the house from the superintendent for himself. It remained the residence of the CNO until 1974, when Congress determined that it would be easier and less expensive to provide security in a government-provided residence, and authorized its transformation to the first official residence for the vice president, though a temporary one. It is still the "official temporary residence of the vice president of the United States" by law. The 1974 congressional authorization covered the cost of refurbishment and furnishing the house.

Although Number One Observatory Circle was made available to the vice president in 1974, more than two years passed before a vice president lived full-time in the house. Vice President Gerald Ford became president before he could use the house. His vice president, Nelson Rockefeller, primarily used the home for official entertainment as he already had a well-secured residence in Washington, D.C., though the Rockefellers donated millions of dollars' worth of furnishings to the house. Walter Mondale was the first vice president to move into the house. Every vice president since has lived there.