Ejin is a banner in the far west of Inner Mongolia, China. It is under the administration of Alxa League and is the westernmost county-level division of Inner Mongolia, bordering Gansu province to the west and Mongolia's Bayankhongor and Govi-Altai Provinces. Its seat is located at Dalaihob Town. To the west, it shares a border with Subei Mongol Autonomous County of Jiuquan, Gansu.

Alxa League or Alashan League is one of 12 prefecture level divisions and 3 extant leagues of Inner Mongolia. The league borders Mongolia to the north, Bayan Nur to the northeast, Wuhai and Ordos to the east, Ningxia to the southeast, and Gansu to the south and west. The capital is Bayanhot Town, formerly known as Dingyuanying (定远营镇) or Wang Ye Fu, in the aimag's Left Banner. The Mongolian variety spoken in this area is the Alasha dialect.