[2] Established in 1830 as the Depot of Charts and Instruments, it is one of the oldest scientific agencies in the United States,[3] and remains the country's leading facility for astronomical and timing data.

In 1893, in an effort to escape light pollution, it was relocated from Foggy Bottom near the city's center, to its Northwest Washington, D.C. location.

The USNO has conducted significant scientific studies throughout its history, including measuring the speed of light, observing solar eclipses, and discovering the moons of Mars.

[4] The Naval Observatory performs radio VLBI-based positions of quasars for astrometry and geodesy with numerous global collaborators (IERS), in order to produce Earth orientation parameters and to realize the celestial reference system (ICRF).

Aside from its scientific mission, since the 1970s the Naval Observatory campus hosts the official residence of the vice president of the United States.

Established by order of the United States Secretary of the Navy John Branch on 6 December 1830 as the Depot of Charts and Instruments,[10] the Observatory rose from humble beginnings: Placed under the command of Lieutenant Louis M. Goldsborough, with an annual budget of $330; its primary function was the restoration, repair, and rating of navigational instruments.

"[11] Lt. Gilliss visited the principal observatories of Europe with the mission to purchase telescopes and other scientific devices, and books.

[12] The observatory's primary mission was to care for the United States Navy's marine chronometers, charts, and other navigational equipment.

By the end of the American Civil War, the Observatory's clocks were linked via telegraph to ring the alarm bells in all of the Washington, D.C. firehouses three times a day.

An early scientific duty assigned to the Observatory was the U.S. contribution to the definition of the Astronomical Unit, or the AU, which defines a standard mean distance between the Sun and the Earth.

This 40 inch aperture instrument[21] was also the second (and final) telescope made by famed optician, George Willis Ritchey.

[22] Within a decade, the Navy's largest telescope, the 61 inch "Kaj Strand Astrometric Reflector" was built; it saw light at Flagstaff in 1964.

[24] By the early 1870s the USNO daily noon-time signal was distributed electrically, nationwide, via the Western Union Telegraph Company.

In November 1913 the Paris Observatory, using the Eiffel Tower as an antenna, exchanged sustained wireless (radio) signals with the U.S.

In collaboration with many national and international scientific establishments, it determines the timing and astronomical data required for accurate navigation, astrometry, and fundamental astronomy, and calculation methods — and distributes this information (such as star catalogs)[27] on-line and in the annual publications The Astronomical Almanac and The Nautical Almanac.

The alternate Master Clock time service continues to operate at Schriever Space Force Base in Colorado.

In the alpine woodlands above 7,000 feet altitude outside Flagstaff, Arizona, NOFS performs its national, Celestial Reference Frame (CRF) mission under dark skies in that region.

Naval Observatory operates two “Master Clock” facilities, one in Washington, DC, and the other at Schriever SFB near Colorado Springs, CO.