Below is the most comprehensive list, grouped by region and noting the type of conflict.
Europe
| Country |
Conflict(s) |
Type |
| United Kingdom (Great Britain) |
American Revolution (1775–83), War of 1812 |
Declared |
| Germany |
WWI (1917–18), WWII (1941–45) |
Declared |
| Italy |
WWII (1941–43, until Italy switched sides) |
Declared |
| Austria-Hungary |
WWI (1917–18) |
Declared |
| Spain |
Spanish–American War (1898) |
Declared |
| France |
Quasi-War (1798–1800) |
Undeclared naval |
| Serbia (Yugoslavia) |
NATO bombing of Yugoslavia (1999) |
Undeclared |
| Bosnia and Herzegovina |
NATO intervention (1995) |
Limited air campaign |
| Kosovo |
NATO-led war (1999) |
Undeclared |
| Russia (Soviet Union) |
Allied Intervention in Russian Civil War (1918–20); Cold War proxy conflicts |
Limited/proxy |
| Bulgaria, Romania, Hungary |
WWII (as Axis allies) |
Declared (as part of WWII) |
Asia
| Country |
Conflict(s) |
Type |
| Japan |
WWII (1941–45) |
Declared |
| China |
Boxer Rebellion (1900), Korean War (1950–53), Vietnam War (indirect), Taiwan Strait crises |
Limited/proxy |
| North Korea |
Korean War (1950–53) |
Undeclared |
| Vietnam |
Vietnam War (1965–73) |
Undeclared |
| Cambodia |
Bombing during Vietnam War (1969–70) |
Undeclared |
| Laos |
Secret War (1964–73) |
Undeclared |
| Philippines |
Philippine–American War (1899–1902) |
Declared |
| Afghanistan |
2001–2021 War on Terror |
Undeclared |
| Pakistan |
Drone strikes, cross-border raids (2000s–2010s) |
Limited |
| Iraq |
Gulf War (1991), Iraq War (2003–11) |
Undeclared |
| Iran |
1988 naval clashes (Operation Praying Mantis), ongoing tension |
Limited |
| Syria |
Airstrikes and proxy fighting (2014–present) |
Undeclared |
| Lebanon |
1983 Beirut intervention |
Limited |
| Thailand |
WWII (brief hostile relations, though minimal fighting) |
Limited |
| Burma (Myanmar) |
WWII (Japanese-occupied) |
Limited |
| Kuwait |
U.S. fought to defend it (Gulf War) |
Ally, not enemy |
Middle East & North Africa
| Country |
Conflict(s) |
Type |
| Libya |
1801–05 First Barbary War, 1815 Second Barbary War, 1986 airstrikes, 2011 intervention |
Multiple limited |
| Iraq |
(see above) |
— |
| Iran |
(see above) |
— |
| Syria |
(see above) |
— |
| Afghanistan |
(see above) |
— |
| Yemen |
Drone and air operations (2010s) |
Limited |
| Somalia |
1993 “Black Hawk Down,” later anti-terror operations |
Limited |
Americas
| Country |
Conflict(s) |
Type |
| Mexico |
Mexican–American War (1846–48) |
Declared |
| Canada (British Empire) |
War of 1812 |
Declared |
| Haiti |
Occupation (1915–34), interventions (1994, 2004) |
Limited |
| Dominican Republic |
Interventions (1916–24, 1965) |
Limited |
| Cuba |
Spanish–American War (1898), Bay of Pigs (1961) |
Declared/limited |
| Panama |
1989 invasion |
Undeclared |
| Grenada |
Invasion (1983) |
Undeclared |
| Nicaragua |
Interventions (1912–33), Contra War (1980s) |
Limited/proxy |
| Honduras |
Banana Wars (1900s–20s) |
Limited |
| El Salvador |
Civil war involvement (1980s) |
Proxy |
| Guatemala |
CIA-backed coup (1954) |
Limited |
| Colombia |
Anti-drug operations |
Limited |
Africa (Other)
| Country |
Conflict(s) |
Type |
| Tripolitania / Libya (Barbary States) |
Barbary Wars |
Declared/limited |
| Tunisia / Algeria (as Barbary states) |
Barbary Wars |
Limited |
| Somalia |
1993, 2000s anti-terror |
Limited |
| Sudan |
1998 U.S. airstrike (Al-Shifa plant) |
Limited |
Oceania
-
No country in Oceania has fought against the U.S.
(Australia, New Zealand, Papua New Guinea, etc. — all allies.)
? Summary:
Approx. 40+ countries have had military conflict with the U.S. (declared or undeclared).
About 150+ countries have never fought the U.S. directly.
