The country has been ruined by decades of war and riven by conflicts between rival warlords and tribal groups.
At the time of the 11 September attacks most of the country was ruled by the Taleban.
The movement consisted of Afghans educated at Islamic seminaries in Pakistan and former Islamic fighters, or mujahideen, who opposed the Soviet invasion of Afghanistan in 1979.
At first the Taleban were welcomed by the population who yearned for stability but their harsh interpretation of Islamic law led to many privations.
The US accuses the Taleban of sheltering Osama Bin Laden and his al-Qaeda fighters, who set up training camps within the country, and believe Bin Laden helped to finance the regime.
Mullah Omar, the head of the Taleban, made Kandahar his headquarters. The town lies on the rich plains of southern Afghanistan, and is part of the Pashtun heartland.
It was one of the last places to remain in Taleban control and some believe Osama Bin Laden may have hidden there for at least part of the war.
The Taleban were removed from power by the military offensive at the end of 2001.
In June 2002 a loya jirga, or grand council, chose a transitional government led by President Hamid Karzai. Elections are due to be held in 2004.
US-led forces destroyed al-Qaeda’s cave complexes and training camps but continue to search for fighters within the country - though many are thought to have escaped to the border regions with Pakistan or further abroad.