The United States has the most diplomatic missions of any country in the world, including 169 of the 193 member countries of the United Nations, as well as observer state Vatican City (but not Palestine) and non-member countries of Kosovo and Taiwan. It maintains 'interest sections' (in other states' embassies) in member states Iran and Syria.
Morocco, in December 1777, became the first nation to seek diplomatic relations with the United States and together they maintain the United States' longest unbroken treaty. However the claim also goes to the Netherlands, as they were the first to recognize the United States as an independent government.
Benjamin Franklin established the first overseas mission of the United States in Paris in 1779. On April 19, 1782, John Adams was received by the States-General and the Dutch Republic as they were the first country, together with Morocco and France, to recognize the United States as an independent government. John Adams then became the first U.S. ambassador to the Netherlands and the house that he had purchased at Fluwelen Burgwal 18 in The Hague, became the first U.S. embassy anywhere in the world.
In the period following the American Revolution, George Washington sent a number of close advisers to the courts of European potentates in order to garner recognition of U.S. independence with mixed results, including Thomas Jefferson, John Adams, Francis Dana, and John Jay. Much of the first fifty years of the Department of State concerned negotiating with imperial European powers over the territorial integrity of the borders of the United States as known today.
The first overseas consulate of the fledgling United States was founded in 1790 at Liverpool, Great Britain, by James Maury Jr., who was appointed by Washington. Maury held the post from 1790 to 1829. Liverpool was at the time Britain's leading port for transatlantic commerce and therefore of great economic importance to the United States. President George Washington, on November 19, 1792, nominated Benjamin Joy of Newbury Port as the first U.S. Consul to Kolkata (then Calcutta), India. Joy was not recognized as consul by the British East India Company but was permitted to "reside here as a Commercial Agent subject to the Civil and Criminal Jurisdiction of this Country...". The first overseas property owned, and the longest continuously owned, by the United States is the American Legation in Tangier, which was a gift of the Sultan of Morocco in 1821. In general during the nineteenth century, the United States' diplomatic activities were done on a minimal budget. The U.S. owned no property abroad and provided no official residences for its foreign envoys, paid them a minimal salary, and gave them the rank of ministers rather than ambassadors who represented the great powers--a position which the U.S. only achieved towards the end of the nineteenth century.
In the latter half of the nineteenth century, the State Department was concerned with expanding commercial ties in Asia, establishing Liberia, foiling diplomatic recognition of the Confederate States of America during the American Civil War, and securing its presence in North America. The Confederacy had diplomatic missions in the United Kingdom, France, Belgium, the Papal States, Russia, Mexico, and Spain, and consular missions in Ireland, Canada, Cuba, Italy, Bermuda, and Nassau and New Providence.
The United States' global prominence became evident in the twentieth century, and the State Department was required to invest in a large network of diplomatic missions to manage its bilateral and multilateral relations. The wave of overseas construction began with the creation of the State Department's Foreign Service Buildings Commission in 1926.
The U.S. has embassies in all states it recognizes with the exceptions of the Comoros, Guinea-Bissau, Libya, Sao Tome and the Seychelles.
The U.S. has embassies (or, in the case of Antigua & Barbuda, a consul) in all states it recognizes with the exceptions of Dominica, St Kitts & Nevis, St Lucia and St Vincent.
U.S. Embassy in Bogota
U.S. Embassy in Brasília
U.S. Embassy in Bridgetown
U.S. Embassy in La Paz
U.S. Embassy in Ottawa
U.S. Embassy in Paramaribo
U.S. Embassy in Port of Spain
U.S. Consulate-General in Quebec City
U.S. Embassy in Quito
U.S. Embassy in San José
U.S. Embassy in San Salvador
U.S. Embassy in Tegucigalpa
U.S. Consulate-General in Toronto
The U.S. has embassies in all countries it recognizes apart from Bhutan, Iran, Maldives, North Korea, Syria and Yemen. It has 'interest sections' in other nation's embassies in Iran and Syria. It also has a de facto embassy in Taiwan.
U.S. Embassy in Amman
U.S. Embassy in Bangkok
U.S. Embassy in Beijing
U.S. Embassy in Hanoi
U.S. Consulate-General in Istanbul
U.S. Embassy in Jerusalem
U.S. Embassy in Kuala Lumpur
U.S. Embassy in New Delhi
U.S. Embassy in Phnom Penh
U.S. Embassy in Seoul
U.S. Consulate-General in Tel-Aviv
U.S. Embassy in Yerevan
American Institute in Taiwan - (Taipei Office)
The U.S. has embassies in (or, in the case of Vatican City, near) all countries it recognizes apart from Andorra, Liechtenstein, Monaco and San Marino.
U.S. Consulate-General in Amsterdam
U.S. Embassy in Athens
U.S. Embassy in Bern
U.S. Embassy in Bratislava
U.S. Embassy in Budapest
United States Embassy in The Hague, Netherlands
U.S. Consulate-General in Hamburg
U.S. Embassy in Kiev
U.S. Consulate-General in Munich
U.S. Embassy in Oslo
U.S. Embassy in Prague
U.S. Embassy in Skopje
U.S. Embassy in Stockholm
U.S. Embassy in Warsaw
U.S. Embassy in Zagreb
The U.S. has embassies (or, in the case of the Solomons, a consul) in all countries it recognizes apart from Kiribati, Nauru, Tonga, Tuvalu and Vanuatu.