In political studies, surveys have been conducted in order to construct historical rankings of the success of individuals who have served as the president of the United States. Ranking systems are usually based on surveys of academic historians and political scientists or popular opinion. The rankings focus on presidential achievements, leadership qualities, failures, and faults.

United States–Holy See relations are bilateral relations between the United States and the Holy See. The principal U.S. official is Ambassador Callista Gingrich, who officially started at her position on December 22, 2017. The Holy See is represented by its Apostolic Nuncio, Archbishop Christophe Pierre, who assumed office on April 12, 2016. The U.S. Embassy to the Holy See is located in Rome, in the Villa Domiziana. The Nunciature to the United States is located in Washington, D.C., at 3339 Massachusetts Avenue, N.W.

Kenya–United States relations are bilateral relations between Kenya and the United States. Kenya and the United States have long been close allies and have enjoyed cordial relations since Kenya's independence. Relations became even closer after Kenya's democratic transition of 2002 and subsequent improvements in human rights.

There have been 40 United States presidential visits to Canada by 13 presidents over the past century. As the U.S. president is both head of state and head of government, these visits have taken many forms, ranging from formal state visits, to official visits, working visits, or private visits.

Fourteen Presidents of the United States have made thirty-four presidential visits to Mexico. The first visit by an incumbent president to Mexico was made in 1909 by William Howard Taft. It was only the second time in U.S. history that a president left the country while in office.

Ten United States presidents have made presidential visits to Eastern Europe and Northern Asia. The first trip by an incumbent president to Eastern Europe was made by Franklin D. Roosevelt in 1945, to the Soviet Union, and was an offshoot of Allied diplomatic interactions during World War II. The first trip by an incumbent president to Northern Asia was made by Gerald Ford in 1974, also to the Soviet Union, and was an offshoot of U.S.–Soviet Détente during the Cold War. The first presidential visits to other Eastern European countries occurred during this era of easing geo-political tensions as well.

Several United States presidents have made presidential visits to Australia and New Zealand. The first visit by an incumbent to these Australasian nations was made in 1966 by Lyndon B. Johnson. His three-day five-city visit to Australia was intended as a show of gratitude to the Australian nation for its then emphatic support for the Vietnam War. Four presidents have traveled there since. Prior to arriving in Australia, Johnson visited New Zealand. He went primarily to shore up support for the war in Vietnam. Only one sitting president has visited since.

Eleven United States presidents and three presidents-elect have made thirty-four presidential visits to Central America. The first visit by an incumbent president to a country in Central America was made in 1906 by Theodore Roosevelt. The trip, to Panama, was the first international presidential trip in U.S. history, and signaled the start of a new era in how presidents conducted diplomatic relations with other countries. In 1928, Herbert Hoover, during the time when he was president-elect, visited the region during his historic "good will" trip, to Central and South America.

Eight Presidents of the United States have made presidential visits to North Africa. The first trips by a sitting president to countries in North Africa were those of Franklin D. Roosevelt, and were an offshoot of Allied diplomatic interactions during World War II. Of the five countries in the region, only Libya has not yet been visited by an American president.

Eight United States presidents have made presidential visits to the Middle East. The first trips by an incumbent president to countries in the Middle East were those of Franklin D. Roosevelt, and were an offshoot of Allied diplomatic interactions during World War II. To date, 16 visits have been made to Egypt, 12 to Saudi Arabia, 11 to Israel, six to both Iraq, Jordan and Turkey, four to Iran, three to the Palestinian Territories, two to both Kuwait and Syria, one to Bahrain, Georgia, Oman, Qatar, and to the United Arab Emirates. No incumbent American president has yet visited: Armenia, Azerbaijan, Cyprus, Lebanon, or Yemen.

Eleven United States presidents and one president-elect have made presidential visits to South America. The first trip was made by Herbert Hoover in 1928. During this tour he delivered twenty-five speeches in ten Central and South American countries, almost all of which stressed his plans to reduce American political and military interference in Latin American affairs. In sum, he pledged that the United States would act as a "good neighbor."

Nine United States presidents and one president-elect have made presidential visits to the Caribbean since 1928. Franklin D. Roosevelt made the most trips to the Caribbean islands (14), either for vacation or while involved with Allied diplomatic interactions during World War II. Of the 13 sovereign countries in the region, four—Dominica, the Dominican Republic, Saint Kitts and Nevis, and Saint Vincent and the Grenadines—have not as of yet been visited by an American president.

Twelve United States presidents have made presidential visits to the United Kingdom and Ireland. The first visit by an incumbent president to the United Kingdom was made in December 1918 by Woodrow Wilson, and was an offshoot of American diplomatic interactions with the Principal Allied Powers at the conclusion of World War I prior to the Paris Peace Conference. The first visit by an incumbent president to Ireland was made in June 1963 by John F. Kennedy. To date, 36 visits have been made to the United Kingdom and eleven to Ireland.

There have been twenty-two United States presidential visits to South Asia by eight United States presidents. The first presidential trip to South Asia, made by Dwight D. Eisenhower in 1959, occurred as the Cold War between the U.S. and the Soviet Union deepened. Both George W. Bush and Barack Obama made multiple trips to the region while in office.

Thirteen United States presidents have made presidential visits to Southern Europe. Woodrow Wilson became the first incumbent president to visit a Southern European country in January 1919 in the aftermath of World War I. Visits occurring during the 1940s through 1980s were offshoots of American diplomatic interactions during World War II and then the Cold War.

Thirteen United States presidents have made presidential visits to Western Europe. The first visits by an incumbent President to countries in Western Europe were made in 1918 and 19 by Woodrow Wilson in the aftermath of World War I. He was awarded the 1919 Nobel Peace Prize for his peacemaking efforts. Visits occurring during the 1940s through 1980s were offshoots of American diplomatic interactions following World War II and during the Cold War. To date, 40 visits have been made to France, 32 to Germany, 19 to Belgium, ten to Switzerland, six to Austria, and five to the Netherlands. No president has yet visited Liechtenstein, Luxembourg or Monaco.