How long was the war in Afghanistan?

The war in Afghanistan began on October 7, 2001, following the September 11 terrorist attacks, and officially ended on August 30, 2021, when the last U.S. troops withdrew. This marks a duration of nearly 20 years, making it one of the longest military conflicts in U.S. history. The war involved various phases, including initial combat operations, nation-building efforts, and a prolonged insurgency.