Yanji (Chinese: 延吉; Korean: 연길; alternately romanized as Yenki or Yenji) is a county-level city in the east of China's Jilin Province, and is the seat of the Yanbian Korean Autonomous Prefecture. Yanji City is located in the eastern part of Jilin Province. It is the seat of the government of Yanbian Korean Autonomous Prefecture and the political, economic and cultural center of the entire autonomous prefecture. Its population is approximately 400,000 of which a significant portion is ethnic Korean. Yanji is a busy hub of transport and trade between China and North Korea. The city is home to Yanbian University, a comprehensive university and the only Project 211 university in Yanji.

Yanji and its environs were largely unpopulated until the 1800s when Qing dynasty rulers of China began to encourage migration there from China proper as part of its Chuang Guandong policy to populate Manchuria in an effort to stem encroaching Russian expansion.

The city was the seat of Jiandao Province in the Japanese puppet state of Manchukuo from 1934 to 1943. In 1943, the city itself was renamed Jiandao (Chientao) and made a part of the Dongman Consolidated Province (东满总省).

Following World War II, the city (again called Yanji) was nominally part of a new Songjiang Province but with the communist seizure of power in 1949, Sonjiang's borders were changed and Yanji became part of Jilin Province.

Yanji is now part of the Yanbian Korean Autonomous Prefecture, which is situated in eastern Jilin. Yanji City is centrally located, surrounded by five other county-level cities and two rural counties (see map); it is the administrative seat of the prefecture.

The North Korean military detonated its second nuclear test in May 2009 close to the Chinese border, and the blast set off an earthquake of magnitude 4.5 with an epicenter only 112 mi (180 km) from Yanji. The mutual goodwill of the Chinese and Korean populations in the region was put under severe strain, and many in Yanji expressed newfound feelings of dismay and insecurity regarding their North Korean neighbors.

A South Korean pastor, the Reverend Kim Dong-shik, was kidnapped in Yanji in January 2000, one of numerous well-publicized North Korean abductions of South Koreans; a suspect of mixed Korean-Chinese descent, said to have been trained in Pyongyang, was arrested and charged with the crime in December 2004.

Yanji was the starting point of an international dispute in 2009 when two American journalists, Euna Lee and Laura Ling, were detained by North Korean border guards when, after leaving Yanji, they overstepped the nearby demarcation line. The two were freed only after intervention at the highest level by former US President Clinton.