The Altyn Tagh Fault extends for at least 1,500 km and possibly for as much as 2,500 km from the West Kunlun thrust zone in the southwest to the edge of the Qilian Mountains in the northeast (and possibly well beyond). It is divided into three main sections: southwestern, central and northeastern. There is one major splay fault, the North Altyn Fault. The main active fault trace of the ATF lies within a zone of secondary structures that is about 100 km wide in the central section.