While the Russian invasion of Ukraine dominated headlines in early 2022 and the countries Germany invaded were a vital part of World War II, the United States has itself been an aggressor on many occasions. Instances of the United States invading non-U.S. territory range throughout the country's history, from the 1805 Battle of Derna in what is now Libya to the 2001-2021 takeover and occupation of Afghanistan.
No single list of countries the U.S. has invaded can be considered truly comprehensive for the simple reason that there exist many differing definitions of precisely which military actions can be classified as an invasion. For example, if one counts only the times the U.S. has declared war on another country and fought on foreign land, there would be 11 instances of invasion spread across five wars.
Countries the U.S. has invaded after a declaration of war:
|Great Britain||1812||War of 1812||Maritime engagements, no war on British home soil|
|Spain||1898||Spanish-American War||Cuba and Spain's Pacific territories, not Spanish mainland|
|Germany||1917||World War I|
|Austria-Hungary||1917||World War I|
|Germany||1941||World War II|
|Italy||1941||World War II|
|Japan||1941||World War II|
|Bulgaria||1942||World War II|
|Hungary||1942||World War II|
|Romania||1942||World War II|
On the other hand, if one's definition of an invasion were to include any significant hostile incursion into another country's territory, even if war were not officially declared, the list could include several more entries. For example, a list compiled by Dr. Gideon Polya of La Trobe University in 2013 included the following:
Countries the U.S. has invaded since 1776:
|Niger||Oman||Pakistan||Panama||Papua New Guinea|
|Philippines||Puerto Rico||Russia||Samoa||Saudi Arabia|
|Yemen||Yugoslavia||Zaire (now Congo)|
The ultimate list of countries invaded by the United States
Finally, if one's definition of an invasion is expanded to include any instance in which U.S. forces interacted with a foreign country or territory—including areas in the Western Hemisphere that were foreign territories at the time but are now U.S. states—one could cite hundreds of incidents since the founding of the country. In fact, according to historians Christopher Kelly and Stuart Laycock, the United States has been "militarily involved" with every country on the globe but three: Andorra, Bhutan, and Liechtenstein.
A more complete tally of the United States' international "use of force" incidents can be seen in the table below, compiled from multiple previously published lists, including those created by the Congressional Research Service (CRS), the Global Policy Forum. Note that even this list should not be considered comprehensive. For example, many covert operations lack a known official record, and so will not appear.
Note that this list, detailed and inclusive as it is, can also be misleading. The CRS counts any event of any size, even those that were just a small posse entering another country to pursue a criminal. The CRS also expressly states that the legality of the events on the list has not been taken into consideration—for instance, if the U.S. sends troops to protect its embassy during a civil war or deploys a deterrent force into a country whose neighbor is amassing troops on its border, the act would likely be considered welcome by some participants and an invasion by others.
As such, the source lists (and in turn, the list below) include many events which may or may not fit one's definition of an invasion. For instance, peacekeeping missions in which the U.S. was (arguably) invited into non-U.S. territory, humanitarian missions such as disaster relief efforts, or WWII battles in which the U.S. landed on the shores of a Pacific island such as Vanuatu—technically an invasion—in order to repel Japanese forces already occupying it. In light of this extreme level of inclusiveness, additional details of each event are included to enable each reader to filter the invasions from the non-invasions according to their own unique criteria.