Ili Kazakh Autonomous Prefecture is an autonomous prefecture in northern Xinjiang, China. Its capital is Yining, also known as Ghulja or Kulja. Covering an area of 268,591 square kilometres (16.18 per cent of Xinjiang), Ili Prefecture shares a 2,019-kilometer (1,255 mi)-long border with Kazakhstan, Mongolia, and Russia. There are nine ports of entry in Ili Prefecture at the national level, notably Khorgas. Directly administered regions (直辖区域) within the prefecture cover 56,622 square kilometres (21.08 per cent of Ili's total area) and have a population of 4,930,600 (63.95 per cent of Ili's registered population). Kazakhs are the second largest ethnicity in the prefecture after the Han Chinese, and make up a little over a quarter of the population.

Ili is the only prefecture-level division that has other prefecture-level divisions (Altay and Tacheng Prefectures) under its administration. The term "sub-provincial autonomous prefecture" (副省级自治州) has often been applied to Ili, but the term has no legal basis under Chinese law and is a misnomer.

Before the advent of the Qin dynasty (221 BC – 206 BC), Ili was inhabited by the Wusuns, a tributary tribe of the Huns. The Wusuns were driven away in the 6th century AD by the northern Xiongnu, who established the First Turkic Khaganate in 552. The area later became a dependency of Dzungaria. During the Tang dynasty (618–907), the khanate became the Protectorate General to Pacify the West of the Tang Empire.

Ili came under the control of the Uyghur Khaganate in the 8th and 9th centuries, the Qara Khitai in the 12th century, and Genghis Khan in the 13th century. The Oirats, specifically the Dzungars, conquered Ili at the end of the 16th or the beginning of the 17th century.^{[citation needed]}

The Dzungar Khanate controlled both Dzungaria and the Ili basin until 1755, when the region was conquered by the Manchu-led Qing dynasty under the Qianlong Emperor. Having defeated the Dzungars in the Dzungarian and Ili basins, as well as the Afaqi Khojas in Kashgaria, the Qing court decided to make the Ili basin the main base of their control in Xinjiang.

In the 1760s, the Qing built nine fortified towns in the Ili basin:

Huiyuan Cheng, as the residence of the General of Ili, the chief commander of Qing troops in Xinjiang, became the administrative capital of the region. It was provided with a large penal establishment and a strong garrison. This city was called "New Kulja", "Manhcu Kulja" or "Chinese Kulja" by foreigners to distinguish it from Ningyuan / Yining, known as "Old Kulja" or "Taranchi Kulja".

The first General of Ili was Ming Rui. The Qing tradition, unbroken until the days of Zuo Zongtang in the 1870s, was to only appoint Manchus as officials in Xinjiang.