List of the lengths of United States participation in wars
This article contains the length and list of major conflicts, invasions and wars participated by the United States Armed Forces since its creation in 1775.
Note that it does not include any Native American wars.
Lengths of US combat forces' participation in wars
War in the context of this list is broadly construed to be a direct armed conflict between organized US military forces and organized forces of belligerent.| Rank | War | Dates | Duration | Duration |
| 1 | War in Afghanistan | 2001 – 2021 | years | ''Sources are found in the main articles of each war, as well as the Associated Press.'' |