This is a list of ambassadors of the United States to individual nations of the world, to international organizations, to past nations, and ambassadors-at-large.

Ambassadors are nominated by the President and confirmed by the Senate. An ambassador can be appointed during a recess of the Senate, but can serve only to the end of the next session of Congress unless subsequently confirmed by the Senate. Ambassadors serve "at the pleasure of the President," which means that they can be dismissed at any time.

An ambassador may be a career foreign service officer or a political appointee. In most cases, U.S. ambassadors who are career foreign service officers serve a tour of approximately three years in a foreign post. Ambassadors who are political appointees will customarily tender their resignations upon inauguration of a new President. As embassies fall within the Department of State, ambassadors answer to the Secretary of State.

Current ambassadors from the United States to international organizations

The United States of America (commonly abbreviated to the United States, the U.S., the USA, America, and the States) is a federal constitutional republic comprising fifty states and a federal district. The country is situated mostly in central North America, where its forty-eight contiguous states and Washington, D.C., the capital district, lie between the Pacific and Atlantic Oceans, bordered by Canada to the north and Mexico to the south. The state of Alaska is in the northwest of the continent, with Canada to the east and Russia to the west, across the Bering Strait. The state of Hawaii is an archipelago in the mid-Pacific. The country also possesses several territories in the Pacific and Caribbean.

At 3.79 million square miles (9.83 million km²) and with over 312 million people, the United States is the third or fourth largest country by total area, and the third largest by both land area and population. It is one of the world's most ethnically diverse and multicultural nations, the product of large-scale immigration from many countries. The U.S. economy is the world's largest national economy, with an estimated 2011 GDP of $15.1 trillion (22% of nominal global GDP and over 19% of global GDP at purchasing-power parity). Per capita income is the world's sixth-highest.

Caroline Bouvier Kennedy (born November 27, 1957) is an American author and attorney. She is a member of the influential Kennedy family and the only surviving child of U.S. President John F. Kennedy and First Lady Jacqueline Bouvier Kennedy.

At the time of her father's presidency she was a young child; after his assassination in 1963 her family settled in the Upper East Side of Manhattan, where she attended school. Kennedy graduated from Radcliffe College and worked at New York City's Metropolitan Museum of Art, where she met her future husband, exhibit designer Edwin Schlossberg. She went on to receive a J.D. degree from Columbia Law School. Kennedy's professional life has spanned law and politics as well as education and charitable work. She has also acted as a spokesperson for her family's legacy and co-authored two books on civil liberties with Ellen Alderman.

In the 2008 presidential election, Kennedy endorsed Democratic candidate Barack Obama for President early in the primary race; she later stumped for him in Orlando, Indiana, and Ohio, served as co-chair of his Vice Presidential Search Committee, and addressed the 2008 Democratic National Convention in Denver. After Obama's selection of then-Senator Hillary Clinton as Secretary of State, Kennedy expressed interest in being appointed to Clinton's vacant Senate seat from New York, but she later withdrew from consideration, citing "personal reasons."

Gary Faye Locke (Traditional Chinese:駱家輝) is an American politician and the current United States Ambassador to China.

Locke was the 21st Governor of Washington, serving from 1997 to 2005. He was the first governor of a state in the Continental United States of Asian descent, and is the only Chinese American ever to serve as a governor. He was then appointed by President Barack Obama as United States Secretary of Commerce which he served as until August 1, 2011, when President Obama appointed Locke Ambassador to China.

Locke was born on January 21, 1950, in Seattle, Washington. A third-generation American with paternal ancestry from Taishan, Guangdong, China, Locke is the second of five children of James Locke, who served as a staff sergeant in the US Fifth Armored Division during World War II, and his wife Julie, who is from Hong Kong, which at that time was a British crown colony. He did not learn to speak English until he was five years old and entered school. Locke spent his early years living with his family in the widely-lauded Yesler Terrace public housing project in Seattle.