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BATTLE // January 1, 2001

United States invasion of Afghanistan

Overview

Shortly after the September 11 attacks in 2001, the United States declared the war on terror and subsequently led a multinational military operation against Taliban-ruled Afghanistan. The stated goal was to dismantle al-Qaeda, which had executed the attacks under the leadership of Osama bin Laden, and to deny al-Qaeda militants a safe base of operations in Afghanistan by toppling the ruling Taliban government. The United Kingdom was a key ally of the United States, offering support for military action from the start of the invasion preparations. The American military presence in Afghanistan greatly bolstered the Northern Alliance, which had been locked in a losing fight with the Taliban during the Third Afghan Civil War since 1996. Prior to the beginning of the United States' war effort, the Taliban had seized around 85% of Afghanistan's territory as well as the capital city of Kabul, effectively confining the Northern Alliance to Badakhshan province and smaller surrounding areas. The American-led invasion on 7 October 2001, marked the first phase of what would become the 20-year-long war in Afghanistan.

Overview adapted from Wikipedia, licensed under CC BY-SA 4.0.

Significance

The U.S.-led invasion of Afghanistan, launched on 7 October 2001 in direct response to the September 11 attacks, marked the opening phase of what became a 20-year conflict. Its stated objectives were the dismantlement of al-Qaeda and the removal of the Taliban government that had provided al-Qaeda a base of operations. The United Kingdom joined as a primary coalition partner from the outset, alongside a broad multinational force. The invasion fundamentally reversed the military balance inside Afghanistan: the Northern Alliance, which had been losing ground to the Taliban since 1996 and had been confined largely to Badakhshan province and adjacent areas, was rapidly bolstered by American military support. At the time of the invasion, the Taliban controlled roughly 85 percent of Afghan territory, including Kabul. Coalition intervention effectively broke Taliban territorial dominance and ended the group's hold on the capital, setting the conditions for the post-Taliban political order. The operation also initiated the longer counterterrorism campaign that would define U.S. strategic priorities for the following two decades.

Forces & casualties

Troop strength

  • Northern Alliance5,500
    medium
  • Islamic Emirate of Afghanistan45,000
    medium

Islamic Emirate of Afghanistan fielded a 8.2 : 1 numerical advantage

Casualties

  • Islamic Emirate of Afghanistan8,000–12,000
    medium22% loss rate

Commanders (33)

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Last verified June 2026
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