Apostolic Nunciature to the United States

The Finnish Embassy in Washington, D.C. is Finland's embassy to the United States. It is located at 3301 Massachusetts Avenue, in the Embassy Row neighborhood.The embassy also operates consulates-general in Los Angeles and New York. The modernist structure was designed by Heikkinen – Komonen Architects and opened in 1994. The Embassy became the first green embassy in the United States, receiving LEED Gold Certification in 2010.The Diplomatic Finnish Sauna Society meets at the embassy.

The Norwegian ambassador to the United States is the official representative of the Government of Norway to the Government of the United States.

The Embassy of Azerbaijan in Washington, D.C. is the diplomatic mission of the Republic of Azerbaijan to the United States. It is located on Embassy Row at 2741 34th Street, NW, NW Washington, DC. The embassy opened on March 6, 1992, after dissolution of Soviet Union in late December 1991. The United States opened U.S. Embassy in Baku, Azerbaijan on March 16, 1992.The chancery is housed in a 1949 building, with a current estimated value of $3,417,500 purchased by Azerbaijani government on March 22, 2000, for $1,595,000. The building is in the District of Columbia Public School District.

Number One Observatory Circle is the official residence of the vice president of the United States. Located on the northeast grounds of the U.S. Naval Observatory in Washington, D.C., the house was built in 1893 for the observatory superintendent. The chief of naval operations (CNO) liked the house so much that in 1923 he took over the house for himself. It remained the residence of the CNO until 1974, when Congress authorized its transformation to an 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 three 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 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. Vice President Walter Mondale was the first vice president to move into the house. Every vice president since has lived there.The vice-presidential mansion was refurbished by the United States Navy in early 2001, slightly delaying the move of Vice President Dick Cheney and his family. Similarly, Vice President Kamala Harris delayed moving in until April 2021 while renovations occurred.

The Babcock–Macomb House is a historical residence located at 3415 Massachusetts Avenue, NW, Washington, D.C. Construction of the house was ordered by Kate Woodman Babcock, widow of former Representative Joseph W. Babcock of Wisconsin. Babcock had had a successful career in the lumber industry while serving two terms in the Wisconsin State Assembly. Upon taking office in the House of Representatives in 1893, Babcock was appointed to the Committee on the District of Columbia. In 1894 he was appointed as chairman. In this position, Babcock gained local popularity and substantial wealth, due to the committee's role in development of the city. Constance McLaughlin Green wrote that Babcock "cleared $400,000 in Washington real estate ... simply by using [his] advance knowledge of which sections of the city were to get funds..."In 1911, Babcock's widow Kate purchased two lots in the newly laid out Massachusetts Heights subdivision, established when Massachusetts Avenue was extended beyond Florida Avenue. Mrs. Babcock purchased the two lots for $14,529 on October 18. The home was the first constructed in the neighborhood, which the city's planning committee hoped would attract the wealthy elite.The architect was Arthur B. Heaton. Heaton opened his own office in Washington in 1900 at age 25. Between 1899 and 1906 he designed houses for the new Cleveland Park neighborhood. From 1908 to 1920 he served as supervising architect for the Washington National Cathedral. During this period, Heaton and his family lived in Cleveland Park, and he designed many buildings for the neighborhood. His residential designs used numerous styles, including Georgian, Colonial Revival, Spanish mission, and the Neo-Renaissance of the Babcock–Macomb House.Mrs. Babcock never moved into the new home. In 1917 she sold it to Tucker Sands, a vice president of the National Metropolitan Bank. Sands rented the house to tenants for two years, until he sold it in 1919 to Army Colonel Augustus Canfield Macomb. The Macomb family lived in the home until 1982, when Edna Wilson Macomb, widow of Alexander Macomb, sold the property to the Republic of Cape Verde, which has utilized it as their embassy to the United States.

The Cape Verdean ambassador in Washington, D. C. is the official representative of the Government in Praia to the Government of the United States.

The Embassy of Cape Verde in Washington, D.C. is the diplomatic mission of the Republic of Cape Verde to the United States. It is located at 3415 Massachusetts Avenue, Northwest, Washington, D.C., in the Embassy Row neighborhood.The Ambassador is Dr Carlos Wahnon Veiga.

The Embassy of Nepal in Washington, D.C. is the Federal Democratic Republic of Nepal's diplomatic mission to the United States. It is located at 2730 34th Place NW Washington, D.C., in the Glover Park neighborhood. The Ambassador is Sridhar Khatri.

The Heurich-Parks House at 3400 Massachusetts Avenue on Observatory Circle, Washington, D.C. was built in 1925 by philanthropic businessman Christian Heurich, Jr. The home was sold to ophthalmologist Marshall M. Parks in 1960. On October 13, 2015, the house was listed on the National Register of Historic Places.

The Embassy of Iraq in Washington, D.C. is the diplomatic mission of the Republic of Iraq to the United States. The embassy is located at 3421 Massachusetts Avenue, Northwest, in the Embassy Row neighborhood, near the United States Naval Observatory.

St. Nicholas Cathedral (Russian: Свято-Николаевский собор) in Washington, D.C., is the primatial cathedral of the Orthodox Church in America and the seat of Tikhon, Archbishop of Washington, Metropolitan of All America and Canada of the Orthodox Church in America.

The United States Naval Observatory (USNO) is a scientific and military facility that produces geopositioning, navigation and timekeeping data for the United States Navy and the United States Department of Defense. Established in 1830 as the Depot of Charts and Instruments, it is one of the oldest scientific agencies in the United States, and remains the country's leading authority for astronomical and timing data for all purposes.The observatory is located in Northwest Washington, D.C. at the northwestern end of Embassy Row. It is among the few pre-20th century astronomical observatories located in an urban area; initially located in Foggy Bottom near the city's center, it was relocated to its Northwest DC location in 1893 to escape light pollution. 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. Its achievements including providing data for the first radio time signals, constructing some of the earliest and most accurate telescopes of their kind, and helping develop universal time. 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, the Naval Observatory campus hosts the official residence of the vice president of the United States.